1-Barbarian is tier 4. And altough DR never hurts, let's be honest, what does it matter DR 1 at 7th level?
You're dodging the issue. Its not about whether or not DR1 is cool at level 7th (and it is). The Xixecal gets it a level 2. It makes a much larger difference at that level.
Some poisons won't work because the damage of the weapon is negated, each time you are dealt damage has a chance to remind you every hit point counts (especially considering the rate of natural healing when you don't have cure magics). Then there is the awesomeness of not being bothered by normal insects, disease carrying rats, walking freely on caltrops you spread yourself around and so on.
6-Look, one of the things many people complain in D&D it's that you can use mental scores to enanche your martial capacity, but it seems like you can never use your physical scores for enanching mystical abilities. Well no more. Monsters should be allowed to use magic with their muscles and/or life force instead of needing to be pretty.
Its pretty much covered in the Tarrasque section.
Though I don't recall people making much of a fuss over it. I think it might be because Str and Dex covers almost everything battle oriented and giving those stats as a main spellcasting ability would allow gishes to fully own in both departments. Most X to Y effects of mental to combat affects a single aspect of combat at a time while an ability used for spellcasting pretty much only offers more spells or better DCs. Once you get both you have the entire mystical aspect covered, making physical to mystical more meaningful and powerful than the opposite.
There are actually a few rare ways to replace a typical mental stat usage with a physical ability score, but are indeed far and few and often very restricted.
I can picture some beast using its blood or lifeforce and losing life to generate magic; I have a hard time imagining a beast creating a prismatic wall with his muscles. Not without laughing, at least.
I will also note that not many spellcasters are getting their main casting stat increased every level either.
10-Yeah that's called synergy.
Which brings me back to the original problem: Now every attack slows and drains Con. It should be doing one or the other. It shouldn't bypass Con damage/drain immunity seeing how those kinds of attacks are way too dangerous to bypass some form of surefire protection. Even 1 or 2 at a time, especially considering all the
synergy. Perhaps a swift action to make all its natural attacks inflict Slow or a swift action to make them deal Con damage/drain would be a balancing factor.
11-See the same argument with the Tarrasque. Also there's no such thing as too high main stats.
Not as valid now considering all the good stuff a healthy charisma score could do to a Xixecal if it was built more in line with the original monster.
The point was not about whether or not getting 2 unheavely high stats with everything else in the abyss was a good or bad idea; I am disputing the notion that such a creature not being able to "afford" the raise a third stat a bit higher than abyssal, considering its major increases elsewhere, might not be a blatant exaggeration.
12-I'm kinda lost here. If casters are the thing to watch out for, what's the problem with defensive measures against them?
Dimensional Lock: level 8th spell.
Dire Snowstorm: Dimensional Lock on crack at level 10. Massive range bigger than the Epic Spell its meant to emulate.
Still lost?

15-Because it's already over lv10 and there's much worse stuff out there by then.
Hearing you, there will always be worse, and that justifies every little injustices like a creature receiving a few uses of a spell inaccessible to any caster its level.
16-Ok, it's good at killing stuff. Adventurers are suposed to kill stuff.
Most are. But they don't all get an infinite number of Quicken Spell-like ability feats.
19-That's what you get for being two levels lower than your oponent.
Or two level higher, no doubt.
20-Because IRON HEART SURGE cannot be used if you're immobilized. All maneuvers need you able to physically act as base rule.
Exactly. I never said otherwise. Only that it cleanses the user of status effects.
This is ways better than iron heart surge and can be used as a mental action. Isn't that good enough? Does it really need to be done faster too?
22-You may not have the balls to deal with high power D&D, but I assure you it exists and can be quite a good experience. My longest running PbP has no less than an abrupt jaunt wizard filled with prcs, a psionic archmage, and a rainbow mage servant war weaver, among others, and all I restrict are endless loops and minion combos. Yes sometimes it breaks down in a player-DM duel, but competitive gaming is still gaming, and pretty good if you know what you're doing. Now I'm not making this classes to stand toe to toe with abrupt jaunt wizards and whatnot, but so that at least they won't fall to a simple quickened spell.
Woah there. Getting personal now?
I had my share of very high power epic and, yes, it is fun when properly managed. I am not anti-super-epic despite whatever impression I may have given you. Sorry if you felt offended by the comment. I forgot to also note the exception where a game without fairness is what a DM offers to his players. I'm saying this with the memory of too many such epics game that went nowhere after or before the first encounter when a DM realized that it was way over his abilities and preferred to abandon the game over asking his players to tone their characters down. What you consider epic gameplay is not the same for everyone else either.
I am saying that Perfect Freeze is a big thing, because it is, and I'll leave it at that.