That's not true. I have players who played gnomes. Not my cup of tea but I see their role in the gameworld. It's not even so much which classes are "older" (half-orcs, btw, were in 1st edition, and beat out Draconians, tieflings, and several types of elves) but half-orcs and gnomes are certainly more established and have a bigger role in people's campaigns.
Gnomes are not a very pretty race I think (even if they have their niche). About if half-orcs are older or not: half-orcs, draconians and several types of elves are all 1e (half-orcs as a playable race, not sure about the others). Tieflings are 2e (playable in Planescape). But then half-orcs were taken out in 2e as a basic race, kind of similar to what has happened here. Could be to sell more PHB2 books, or could be because they aren't very popular either, no idea.
Now, I didn't say 3.5 was balanced. 3.5 character builds are infamous, but it's partially the GM's discretion to allow or disallow these builds. I personally wouldn't allow that unless the game was particularly silly.
I think I misanderstood you in the balanced point. Agreed 3.5 is very easy to break.
You still haven't told me what you think about the new rust monster rules, btw. Do you think that's acceptable?
Yes, why not? The 3e rust monster comes from a tradition of monsters that are just designed to correct a problem with the GM (too many magic items in the group) and not because they are good monster themselves. There was another monster just designed to hit people listening through doors in dungeons (don't remember the name) who was just another nonsense to avoid people listening through all the doors (another GM problem).
4e rust monster is better designed as a monster itself. It continues to be a pain (as you have to recreate the magic item) but not such a pain as the 3e version.
Well, if you could call it "multiclassing". I find the multiclassing rules in 4e just incredibly meek. The system in 3e certainly was not perfect, but it was simple and it was powerful.
3e system was simple in the rules, but not in the design implications, and that's why it never got to work well: multiclassing produced far more powerful (Pun-Pun and other broken builds) or far less powerful characters (spellcasters with non-spellcaster levels in general) than non-multiclassed ones, instead of more or less equal characters. 4e has some broken builds (I think that's impossible to avoid), but all characters have more or less the same utility, multiclassed or not.
You still haven't addressed what I think is the worst element of 4e: The staggering of material. How do you feel about having to buy two monster manuals to get all of the classic core monsters, or two players handbooks to get the classic core classes, or just to get half-orcs?
I haven't addressed it because I don't see it as a problem (or at least is not for me). I got some material in 2e, another different material in 3e and another different material in 4e. For me classic core is human, elf, dwarf, halfling, fighter, cleric, wizard and rogue and I do get that, so I don't have any problem if they add further material in other PHBs or MMs (appart that I have an insider subscription, so I couldn't care less about the physical books ).