well, games left without support do tend to die more easily than ones which are upgraded regularly...
i would also like to see map pool changes (some maps can as well be written off, or replaced - the ones no one plays) and map balances, but meta-game can evolve only to certain point without any balance changes. when that point is reached, game become kinda stale - no new strats, games start to be increasingly similar to play/watch etc...
i won't deny - i desire a balance patch, and having one would increase my game-time greatly. i'm sure many people feel this way and that, much decreased, number of players would quickly climb up if proper patch was released.
sadly, blizzard is unlikely to do so while simultaneously develops D3, SC2exp, WoWexp and new MMORPG
so, to answer to OP and stop fantasizing about new patch:
- WC3 won't die in next few years (that's what i voted for). it WON'T be replaced by SC2, but may be with WC4, since bnet2 have lots of improvements and honestly - which fan could resist having it. however, smaller WC3 community may remain even long after WC4 (hopeful) release, as it happened to RoC