i'd like it, cause the combos we have now are kind of done so that the 2nd skill starts where the 1st animation ends, but with all the down-time, it feels really disconnected, and not really like a combo at all - you go back to idle pose, before being able to start next skill.
the problem is that you can cancel animations by using another skill, so with no CD you'd cancel your combo animation, which would look stupid.
if they made it so that the next skill is qued instead, for after prev animation ends, then long animation skills, would reduce your DPS, so they'd have to speed up the animations to fit into the 0,5sec time-frame where you can't use another skill...and that would be awkward.
it would burn through your TP in seconds, rather than minutes, so they'd have to re-design the entire resource system.
so basically...no, it's a terrible idea