First of all, I don't claim to be an expert on Champ build. They're relatively rarer compared to templars at the moment.
But what I've seen is that champs seem to need timing on their reflects (which I would suggest getting as a skill). In terms of skill build, you can always reset using the skill reset potions (just buy for tears). Suggest learning the skill timings and just try things out really. Plus you get that cool healing skill.
For SP, have you done all the extra SP quests?
http://noscrubs.net/discussions/guide-quests-that-give-extra-skill-points-sp
In terms of gear, champ is pretty interesting to build. Def and abs aren't as important because the higher those are the less useful your reflect skills are.. but at the same time you do still need at least some to survive the hits. Another thing you need to survive (in order to reflect back) hits is HP. So you do have choices as to how to approach it.. no perfect build yet though I think
Some champs use the HP wings instead of Def wings.
In terms of equipment, yes CQ stuff is nice, but it's pretty troublesome to get if you don't have a party/hate farming for ores. The next best and much more affordable alternative would be the gear that drops from TOAI. You'd have to buy it though, since with no gear you cannot tank it.
In terms of holding aggro, it's challenging to gain aggro from mobs compared to a templar (no constant regen rope). But it seems to be good at holding solo bosses aggro since you'd be hitting the boss + getting aggro from the reflect. so aggro would depend on your teammates (and whether they are too impatient to let you get aggro)
just my 2 cents ~