If the LD line of products is profitable and stays (palmOne included) then about the only improvements we will see in the shorter term are small incremental ones as they don't cost much in terms of product change and continued marketing vs a totally new line or product launch.
Don't expect anything groundbreaking from palmOne for quite some time with Symbian and WM05 coming on strong. OS7 [Linux] had better be some kind of incredible improvement or we may not be seeing too many more palm based PDA's unfortunately I fear.
As powerful as PDA's are and bridging the gap as laptop replacements in some markets, there's not a whole lot more they can do except for software improvment and some minor hardware tweaks (stand alone pda). Better screens (VGA) and larger storage along with possibly a slightly faster processer are about all we can expect from palm, plus some minor things like what PPC's are doing like video out and other minor things but those are only useful to niche markets. They don't have the dominance anymore and are risk averse to bring out anything "groundbreaking" whatever that could be (not sure) and survive a possible flop.
What I'd like to see is more built in RAM vs HD based ram. More dynamic heap memory so you can emulate and play bigger games like zDoomz or others to come. Plus video out. Possibly a slide out keyboard.
Actually a T|E2 would actually fit me better if it had wifi as I'd rather have the storage on a removable flash memory. Better battery life, easier transfer, doesnt' get lost on a hard reset. Plus with the announcement of 4GB SD cards likely to keep increasing over the next few years, personally I don't see a moving, battery draining, fragile harddrive as something I want in my PDA. Course that's just my worthless opinion (I do have a LD and like it mostly).