Before we start - I can tell you have only read the list and not playtested it. Therefore you can see how you would find a lot of faults everywhere. I hope you will test it and come up with options rather than just read pieces and pick at details you find startling.
Woah, I don't mean any offense. Just thought you would appreciate more people saying what they think about it.
I'm not going to playtest it; I don't have any squats. I'd love to read about any playtests.
If I sound like I'm saying I know the list inside-out, I apologize. Obviously, I don't. I consider what I have to say to be almost inconsequential in comparison to the playtesting you've done.
That is why Brother in Arms applies. They are not immune to everything, they are still basically a militia, which is why they have the Ld they have.
I kinda wonder if the Brother in Arms rule is really appropriate instead of just a plain old higher Ld. With your rule, it means that squats aren't any more courageous when they're on their own, which seems like it'd be more appropriate to space skaven or goblins than to squats. It also means that they're still vulnerable to everything else Ld based-- pinning, mind war, whatever. It's not how I see them, and it seems like special rules for special rules' sake.
Playtesting shows this to work well, as Orks and Tyranids are by far the best to wipe out the Squats. It has not posed a problem so far. Have you tested it?
Are orks and tyranids really the toughest armies for your squats? This list looks well-equipped for them. In my opinion, if a list needs a bonus against some other particular list, then it's because of a hole that can apply to other lists. "Preferred enemy" is a rule used by GW primarily for fluff purposes, not for balance. The inclusion of furious charge against orks only is unprecedented-- which is okay if that's what you really want, but I wonder if that furious charge is really that important to your squats, or if you'd rather emphasize other elements of the squats. The more weird rules you throw out there, the less important each individual difference becomes.
Can you see a way to make it [berserker] less cumbersome?
Existing USRs that well represent berserkers are Furious Charge and FNP. If you feel like toning either of these down, it seems like it would make sense for berserkers to always be hit on 3+ in close combat.
[Re: force shield] Any chance of a constructive idea rather than just criticism? These were in RT, this is the RT-list. That is why it is here.
Sure, there's a million different things you could do to force shield. (Let's not forget that RT also had steal-a-unit psyker powers, vortex and virus grenades, and 60"/turn powerboards.) The ability to advance an army under the cover of a double-tough landraider sounds like it would be both tempting and not much fun for either player. What if the unit could only gain the save in lieu of movement? That would reinforce the idea of squats as slow but tough. That's what I'd try first.
Psykers in RT blew armies apart. This is pretty much what it could be balanced down to in 4th ed without becoming silly. And the powers have been toned down over and over to allow two uses. In 2nd ed they could use 4 powers, all of which seriously more devastating than any of the ones available here.
But this list isn't balanced against RT psykers-- it's balanced against 4th ed psykers. If you preserve the power of RT psykers in your list, you lose the fluff of squats as sub-par psykers, who are, at best, capable of matching regular ol' humies.
[Re:Strength stat] And how should be progress in power then?
Current armies rarely have a bonus to S for mortal heroes (as opposed to monstrous heroes, or legendary characters). Squats, who really seem like they ought to be around S3.5, assuming that were possible, could get away with S4 heroes, even if that was inconsistent with other lists. To range from S3 to S5 without the aid of special equipment or some kind of size increase is another one of those "woah that's weird" things that should be justified by fluff-- and I don't think the fluff justifies it.
[Re: bikes] And again, what would you suggest?
I would think that the right price for a guild biker would be between 20 and 25 points a model. I think that the right price for a HW trike should be about 50 points a model. Of course, you're the one who's done the playtesting, but if I was to build an army from this list as it stands, with the aim to win a game, the very first thing I would take each time would be 3 HW trike units.