So long story short: I'm going to a Tournament where a lot of monsters have a few extra rules to make them more appealing (All Giants have 4+ Regen etc.) and you cannot have duplicate Warmachines or rare choices (but 2 Bolt Throwers and there are a few exceptions). And unit sizes are rather restricted: more pts/model = lesser unit size. as an example Sarus are max 25. The Troglodon gets to use his Roar D6 times a game. Do you think this makes the Troglodon worth taking? If we assume that we roll an average 3-4 for each game. We more or less gets to roar on any important combat phase we would ever need it in. I do think this significatly bumps up its potential and that it might be worth taking, but I am interested to hear what you guys say. Furthermore the Carnosaur gets both upgrades for free. I really think this also makes it far more valuable. It is 40 pts for free (if you get use out of both upgrades ofc.). Furthermore restriced unit sizes also make the carno shine more vs cavalry etc. I think.
Restricted unit sizes makes Roar worse. You're less likely to have Saurus still around to get the extra attacks, and saurus aren't really a good choice for fighting monsters; skinks are. In the setting you're talking about, unless you load up on temple guard near a bastiladon (for Init3) or Saurus Cav (can't be thunder stomped on) I don't see Roar as exceptionally good even then. Steggadons on the other hand, are really good, and the rules in use make them even better. Go skinks + steggadons, and bunker for slaan (or ethereal slaan is good in a monster mash).