Only if it wasn't limiting in an exclusive fashion. I.E., if it was set up so that if you mastered Destruction you could no longer excell in and master conjouration, then no, I absolutely would hate that.
If, however, it left you with options open as a role player, so that if you wanted to excell in only one school and be recognized for it that would be fine, but you could also, if you choose and had a desire to have the moniker of Archmage rather than merely Destruction Master, applied to you, then you could go down the various paths in a non exclusive fashsion, offering aid and advice to various sub-factions within your guild, then I would be ENTIRELY for it. It would make the guilds more rewarding and fullfilling I think, and offer longer and more thorough side-quest quality and opportunities.