The problem with fragile chains is that there is very little interchangeability between leads. The shortest chains so far that have existed is 4 skills, not 3, due to the fact that most chains have only one usable lead attack as opposed to two or three. If there are multiple leads, then an assassin won't have to worry about being disabled as much. Inconvenient, yes, complete shutdown, now.
Ritualists:
The thing is, minions can mob a single target, can move with the party, and is extremely cheap to make (especially on a necro). Whereas spirits give no such benefits, hence my desire to see the spirits being buffed to be higher than a necromancer. Further more, sane ritualists should be throwing up the correct spirits to fit the needs, not spamming them. See a spike? Throw up Shelter for party wide damage negation. See a fire ele? Throw up dissonance for quick interrupts. Etc, etc.
I'm actually different on the spirits being easy to kill side. I like them being more difficult to kill so I can get off even more death blossoms instead of only getting to the off-hand. And because spirits tend to be surrounding the ritualist caster, I can take down the caster and all of his spirits in one go instead of doing them one by one.
Paragons:
Actually, I'm of the opinion that paragons need to have less adrenalin build up than warriors, but that paragon skills should be more energy based than adrenalin based. The point of a paragon is to build up energy through shouts and chants, most of which function on at most 5 adrenalin, as opposed to some of the warriors' 8 to 10 adrenalin skills. So a spear should attack slower than a sword but do comparable damage, hence short bow equivalent.
Dervish:
My beef with dervish is that they already deal huge amounts of damage through their scythe weapon and enchants (heart of holy flame, balth spirit, etc.). Hell, I've seen 666 damage on the critscythe against a level 20 foe, and that's not really any different from a dervish other than the less chance to see a crit. I really don't think dervishes are lacking in the damage department.
Mesmers: I agree with hex based interrupts (web, backfire, etc.), but I think the point of a mesmer should still to be interrupting. Because what better way to negate damage than to have the skills never get off, right? They just need skills more useful for interrupts on human players.