Well it looks like all you're really getting of substantial value from your 7 Arti levels is BE and Insightful Strikes. Runearms, without many Arti levels, are less than effective, aside from maybe a way to put Banishing/Disrupting/Smiting on your attacks.
So, compared to going pure Rogue, I have to ask - and I'm legitly asking, I'm not sure, but this is what I'd be worried about:
-Does the to-hit from Insightful Strikes really make that big a difference, vs. say, the extra sneak die from pure rogue, feats and enhancements from a rogue-fighter splash, or something?
-EF is only 5/rest, unlike Manyshot-10KS which are both unlimited use with cooldown. Is it worth it going 6+ deep in Arti just for 5 charges of EF and a +2 enhancement? A 2-deep splash still gives you repeaters (which Mechanic does too, of course) and runearms. 3 deep and you keep Insightful Strikes, too.
Especially in EE content, I imagine rest shrines are going to be few and far between if you're using EF as your main "alpha strike" for CCing groups of trash mobs between boss fights.