I have a cheap 10.5in palmetto state upper on a lower using the Troy PDW stock system.  It's got their proprietary bolt/buffer system they came up with to shorten the stock.  I'm also using the buffer spring they provide with the stock kit.  
I've got now way to switch out to a lighter or heavy buffer (at least that I know of).
With the brass ejecting at 2o'clock, will this lead to a problem in the future?
So far thru about 500 rounds this carbine has been very reliable.  Mixed .223 and 5.56 brass mostly 55gr.

No.

2 o'clock is fine.

2:00 is ok, but if it's 2:00 unsuppressed when you suppress it you would want to go to an adjustable gas block or go with an adjustable carrier group.

JPK

eventually I'll have a AAC M4 2000 on this gun.

Then, when you get around to it, swap out the gas block for an adjustable gas block, or swap BCGs for either a Gemtech SCG or a Bootleg SCG. Cheaper option is the gas block, and I use them because they are cheaper, but I think the adjustable BCGs are the better option. Superlative Arms gas blocks get great reviews and are +/-$30 less expensive than SLRs. I have SLRs, and they work well, but my next one will be a Superlative Arms.

[If you go with an adjustable gas block, the two I recommended are adjustable from the front. You will want that feature so that you can adjust as needed without having to take off the hand guard, which can be an issue with side adjustable gas blocks if the MLoc or KeyMod or other holes in the hand guard don't line up with the adjustment screw.]

Even unsuppressed, tamping down the gas for 4:00 ejection will smooth out and reduce felt recoil. Recoil ain't much, but a smooth shooting rifle is more of a pleasure.

The buffer weights in the carrier are the same size as standard weight, I believe 

and KAK makes an adjustable buffer "kit" that has different weights you may be able to use the weights in the kit to swap into the troy carrier 

Let's say I don't change out my bcg (because I can't) and I don't install an adjustable gas block.  
Am I going to run into problems?

Aside from the absolutely certain maximum felt recoil and herky-jerky, unsmooth recoil and beating up all components more than nessecary - which leaves short term reliability, the answer is maybe, maybe not.

Too early bolt unlocking, too much BCG velocity, too fast a cyclic rate, all symptoms of an over gassed condition, can lead to pressure issues, short brass life, failure to strip a round from the mag, failure to lock back and other problems.

What size is the barrel's gas port? Carbine length gas system, right? Answers might help predict trouble, or predict high wear areas, like bolt lugs.

I have a PSA premium 10.5" upper carbine gas length, standard BCG, with an AAC Brakeout 2 flash suppressor. It's on a mil spec lower with an H3 buffer. It ejects m193 at14:00 when unsuppressed. When we put the M4 2K on, it would FTE and the spent case would cause the new round to get wedged under it. Way over gassed IMO. It will run suppressed with Tula Ammo but I don't want to run too cheap ammo through it and I don't think the wear and tear would be worth it. I don't have it with me to disassemble to measure gas port size.

Those are symptoms of too much BCG velocity and too high cyclic rate.

When you shoot supressed your brass may be showing signs of high pressure as well, since the bolt is unlocking while chamber pressure is still very high. The bolt opening early is, in effect, creating excess headspace. I would bet that measuring unfired and then fired brass will reveal case stretching and base expansion. Tough on the bolt too, and it will surely shorten its life span.

A heavier buffer might treat some symptoms, but reducing gas is the cure for the issue.

A less expensive route than an adjustable block would be a Baby Govnah gas block drilled to limit gas. The folks at MicroMOA will give you suggestions for the right bit size. The Baby Govnah is non adjustable, but you should be able to set it up to shoot your favorite ammo at 4:00 unsuppressed and still function reliably suppressed with that ammo and ammo producing similar pressures.

JPK

2:00 is fine

if you want to change it you can use different bugger weights, change the spring strength/length or the bst option is use and adjustable gas block

I have Syrac Ordinance gen I and II and el cheapo Radical adjustable gas blocks on my 556 and 300BLK guns, all 10.5 inchers.

All work fine.  The gen II syrac has Noveske name on it. Super easy to setup and adjust.

You could possibly run into issues if you plan to keep you brass to reload. other than that a little more felt recoil than what you would have if you tuned it with the can on.

Or you may have the problems described below. You will only know for sure when you try it.