Great champion, here is my 2 cents...
Passive- Way OP, the hyperist of hyper carries master yi gets 100% extra damage every seventh auto attack (that also cannot crit). Your guy would get 350% extra damage in the same time and i assume that would go up with crits. The numbers need adjusting....i believe corki gets 10% added as true damage, which would compare to master yis as 70% over the same duration, but ignoring resistances would come out around the same.
Q- is good as long as the spread is not too large...im not sure of the damage but it should be roughly the same as garen spin, considering he is safer then garen using it from range, but it is also easier to avoid. good spell.
W- I like the spell and i like that its AP keeps him in line with most ranged carries. The CC is too strong though...at max level an AOE 2.5 second fear is better then most ultimates for other champions, consider a slow or a brief knock up.
E- Great spell, shield have great usage all game, i would switch the scaling to AP, up the ratio maybe call it an armour power up where his armour glows and sparks and he gains 15% move speed while the shield holds or something.
R- Works very well...if it were me i would make it scale with .40ap / .50ad, and have it so during the channeling you select where all three bombs will land then have them crash down in order one second apart. That would allow you to have it deal lots of damage because of how much skill it would take to predict hitting all the bombs.
stats- Keep in mind that a ranged bruiser is inherently unfair, he gets the benefit of not closing the gap so he cannot be as tanky as a melee or he would win every fight. There has to be a trade off. If you look at existing LOL champions ranged carries are generally 305 movespeed as they can attack from anywhere, and because positioning is their task in team fights, melee champions are allowed to be 320 otherwise they would be kited to death, mages get 315 because they have a little of everything to do.
overall i really liked the champion, i picture him kinda like a fallout powersuit.
if you feel like returning the favour please review for me at http://na.leagueoflegends.com/board/...highlight=echo thanks!
update 9/12/12 - no review for reviews here