Yes, anything with lots of AoE hits (Devouring Orb) that proc ailments (Future Strike in your case, but ignite/poison/etc are probably the same) can really slow things down. My build is the same but worse, due to the large number of AoE hits from Shield Throw in addition to all the hits from Devouring Orb proccing Future Strike.
It’s not the repeating skills per see that’s the problem I think, but the large number of calculations all of the AoE hits require/produce.