My primary issue is that a lot of things seem arbitrarily priced, with no real thoughts aside from "I want these guys/this guy to be awesome and cheap!"
Case in point:
White Lions VS Templeguard
Temple Guards cost 1 point more than White lions, or 7,5% more.
Statwise, Temple Guards have +1 Attacks and +1 toughness and +1 AS in melee, but the same against ranged attacks.
White Lions have +1 Movement, +1 WS, +4 BS (Which is pointless, i know), +1S (GW compared to halberd) and +3 Initiative
Special rules are the breaker, obviously. Coldblooded makes their otherwise equal Ld better, but White Lions have stubborn, which Templeguards can only get if you pay for a slann. The extra attack temple guards have, only applies in the first rank - and this is countered by the White lions "Martial prowess", which means that at 3+ ranks, white lions have the same number of attacks, not counting Predatory fighter - which, if going by front row attacks only, is unlikely to ever be more than 2 additional attacks.
White lions strike at +1 S compared to the TG. They have GWs, but because of their innate ASF, they still strike first against most non-ASF attackers anyway, at initiative 5. They also have Forest Strider, which makes the more versatile.
Templeguards become stubborn with the slann, and automatically passes look-out sir attempts.
So to summarize:
Templeguards are better at:
-Toughness
-Protecting a Slann (Look-out and stubborn)
-Each PF attack is 1 attack more than the WLs
-1 better armour save in CC
White Lions have better:
-Movement
-Weapon Skill
-Strenght
-Initiative
-Always stubborn (Doesn't get taxed to activate this ability either)
-Forest Strider
-Cheaper
So Templeguards primary benefits (Stubborn and auto-look out sirs) require a massive tax, and puts the entire unit at risk from miscasts. They are marginally more durable in close combat, and the attacks are barely worth mentioning.
I can't think of 1 good reason temple guards costs more than white lions. Worse, if we go by supporting choices, White Lions are still better - A High Lore mage can grant them a good ward save with a few casts, they can pick a banner that makes the unit all but invulnerable to all magic, weapons included, and have units that can force -1 S and ASL on enemies in close combat with it - We Lizardmen have nothing this powerful to back them up. We also have access to the same lores, and the ward save is argueably better if you want to reinforce their powerblock.
So despite being better at everything, having better stats and rules, AND better supporting choices, White Lions still cost 1 point less than Temple Guards. This alone makes me sincerely believe that there is no "system" to determining point values, other than author bias, or "gut feeling" as some people call it.