I wouldn't think speed is a concern going forward with Parish, Merrett, McGrath the core and Raz, Walla etc on the edges. Obviously Heppell isn't quick but that's ok, it's not full meat grinder slow. What we do lack is big bodies (Cripps/Watson/Kennedy types) although there's some view that Laverde/Langford/Begley could be thatDaniher & Lynch >>> Lloyd & Lucas.
But Zaka is a good signing for Ess. Midfield speed is an area of concern. One of not many.