I would say if the community wants one then have one at launch. If it fails just roll it in with a current server later on like EQ did with all the old servers. The idea does not appeal to me personally but then again, no one is making me play on that server so why would i care if there is one?
Kinda reminds me of Enron's idea to sell bandwidth. The thinking was, here is a hard working U.S. customer paying for 24 hours of connectivity to the internet, but what about when they sleep? we can sell the bandwitdth time the U.S. customers are paying for!- while they sleep! I mean, they;lre not using it, right? free money!. Where is Enron now? probably not such a good idea. if I suddenly get a Dennis Leary vibe and want to surf for how to make mulch with hot-dog relish smeared on my thighs, I dont want to be locked out because Enron sold the time I already paid for.
The idea is interesting, not a completely horrible idea as some suggest. I probably would not play on a limited playtime server as the population would be lower and most players would target peak times to play. I think my efforts would be better spent looking for a good group of limited play time people and form a guild and set up times we can play together. With respect to slowing progress of the entire server i don't see any reason to do that.
Can you imagine how long an epic weapon quest would take with a 3 hour a day play cap? You'd have to pretty much do away with anything that involved potentially long camp times because people would not want to waste their 3 hours doing quests. Stein of Moggok back in old EQ? Without the proper speed buffs and luck, that could turn into a 3 day affair. Raid nights even for casual guilds can last over 3 hours. Forming up, heading out, clearing to boss, re-buffing and engaging all take time.