My thoughts on 8th edition
I did hear one rumour that the BRB would contain scenarios with objectives that would require core units with banners to capture them. Combined with other changes, this might be enough to make skrox units viable with their speed being pretty high for infantry. The trick would be supporting them enough that they can then HOLD the objective. Too early to tell.
There might be some sort of Horde rule, where units 10 wide can fight in 3 ranks and the front row can always attack even if not in base to base contact. 30 skinks costs only 150 points... just sayin! In addition, all shooting units will be allowed to fire in two ranks... this will make a pretty nice stand and shoot reaction with 20 poisoned javelins! Would also help fill out the requirement for 25% core, which seems like a pretty solid rumor at this point. I initially thought it might be cool to do the 10 skink wide skrox horde, but I'm not sure you gain much from this as the skrox can already fight from the second rank anyway. My setup would probably be 22skinks with 2 krox in this setup, if I do choose to run them...
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You want the kroxigors for their leadership and fear causing at least (whatever fear will do.. probably something useful). This way the kroxigors will usually get to both fight whatever is in front of the unit and the eight skinks in the middle back ranks will get to throw in their attacks as well, with 16 shots on stand and shoot still. It's all very theoretical still.
Speaking of Kroxigors, they will be getting some form of additional "crushing" attack for being larger than normal infantry. Not much detail on this yet.
Magic is supposedly up for huge changes.
1) The ENTIRE core spellbook is being re-written, and mega spells possibly being added to each lore. We're talking game-winning spells being a possibility, and who would have a better chance of casting such spells than the mighty Slann? Not to mention the Slann will have access to 8 super spells! I will most likely do a magic roundup for 8th edition, once it comes out and I get my greedy hands on a book.
2) I've heard that spells might be selected, and not rolled for. This would eliminate the need for Focus of Mystery for the most part, though plaque of Tepok will probably be popular for the Slann. That way you just pick one spell NOT to have in each lore, and take the other 5. (Of course assuming each lore still has 6 spells.. if they have more than 6 spells per lore it's a different story!) Depending on how the re-written lores of magic stack up in usefulness, it may only be desirable/necessary to go with the default 4 spells. Though with the skink priests choosing their own spells as well, the plaque might as well go to the Slann. Speculation on my part... will this mean a caster's spell selection will become part of the army list? Not rolling for spells means you can pick spells to specifically complement your own army, but allows for less game-by-game flexibility in tournaments and such. Again, the last bit is my own pure speculation.
3) Irresistable force might be getting a downside. Not much we can do about this, should hit everyone evenly.
4) Miscasts might be less common, but even more devastating. This would make Cupped Hands of the Old Ones a must-have choice on the Slann, to save his bacon and ruin the enemy's day (even moreso than before)! If each of the Lores has a super-spell, it will be really tempting to just launch a ton of dice at it with the Slann, and not worry too much about miscasting so long as you got the Old Ones watching your back.
5) Random pool dice generation. Magic phases will be randomly bigger or smaller based on how many power dice you roll up for each phase. What this says to me is Focus of Rumination is getting even better. Say you roll up more dice than normal, +1 dice per casting attempt on the Slann will make an above average magic phase into a super-devastating one. Not much certainty on how many dice, but it seems you will roll 2d6 at the start of the phase and get bonuses based on how many mages you have. It also makes it sound like casters won't have "their own" dice, so a skink scroll caddy could potentially donate his power dice to the Slann (by way of the power pool). Depending on how this adjusts average number of power dice per phase, bound items like the jag charm could see a bump or a drop in effectiveness (not to mention, they may change what the Steed of Shadows spell does!)
Movement
Moving blocks of troops will be "more flexible", and maneuvers will be enhanced by command models such as champs and musos. Changing the functions of command groups might turn them into something that gets taken on every unit. Increased flexibility will be something our saurus and skink blocks enjoy as well.
Some random element to be added to charging. Either charging will be your normal move + D3 or D6, or charging might grant these bonus rolls on top of what you already get. Some people are dead set against making charging random in any way, but really you will still need to be able to assess ranges. It makes it more like guessing range on a cannon... you have to figure out about how much extra the dice will give you on average. Overall it makes charging less reliable, but the person being charged will also have to weigh his options when fleeing charges... he might flee hoping his charging opponent will roll low and get wiped out for it. I personally don't have a problem with this and think it will add a new element of risk to charging and get rid of the artificial feeling of something charging from almost exactly its maximum charge range. I personally think this will place more importance on manuevering itself and not so much on which model has the higher movement statistic.
Heavy Cavalry 2+ armor or better, can't march. Cold ones won't be the fast strike force they are now, and will be more of a support for the saurus. The upside is, you won't lose much by failing an early stupidity test, they can't march anyway! This might also shift preference towards kroxigors as shock troops, since they will be able to march 12 still and gain bonus crushing attacks.
Autobreak from Fear/Terror is gone. This isn't bad for us really, and actually fear and terror are supposed to add flat combat resolution bonuses to combat. Can you say "flank charging Salamander"? So since Stegadons are immune to psychology, they might have a leg up on terror causers who aren't immune to psych. "I cause terror, so I get +2 combat res." "Well, my stegadon is immune to psych, but he also causes terror". Long live the stegadon! No word on whether the terror tests will stay, but I would assume so at this point.
One save to ruin them all! Basically this means you will only be able to take one save attempt at each wound. So if your Oldblood has 1+ armor and a 5+ ward, against an arrow you could take your armor save, but not your ward save if you fail your armor save. Likewise if your armor bonus is reduced and 5+ ward is better, you take that one. It also seems like the Engine of the gods won't need to protect saurus from shooting anymore, as most shooting will allow the saurus a 4 or 5 plus armor save anyway. This changes if warmachines are on the field, but overall the "shield bubble" is less universally useful. To me this sounds like combat characters will be less durable overall, so if I had to put money on it right now I'd say the Slann will still be the preferred lord choice. Though of course this could change depending on the allowed percentages for characters.
That's all I got for now, really looking forward to this new edition, it should be an improvement if more emphasis is placed on troops.