Strict Classes does = challenging in MMO standard, you are talking about search times for other players as if this were XI...need I remind you the point of "searching" for a class is completely MOOT when you can change your job/class where ever you want?

Strict Class setup creates a PARTY challenge, not an individual challenge, and I think that is the biggest thing people are not realizing, this is an MMO; personally I feel it should be Party dynamics 1st, solo dynamics 2nd.

The challenge I feel you would get is having to RELY on other people to lend a hand, something that is unique to the MMORPG experience versus an single player RPG.