I actually have a very similar squad.
http://www.bloomilk.com/Squads/View.aspx?ID=76797In my experience, the Whiphid isn't nearly enough range support to last you through a match. The Storm Commando is a strong shooter (plus, he gets Advantageous and Opportunist) and he packs in Satchel Charge, removing the need for the Engineer. R7's a good option if you're squeezed for points. Otherwise, I would go with CLObot, then you've got two sets of Reserves working for you. Grans are good. :)
In answer to your question, the basic idea is competitive, it just needs some polishing. Map choice is also crucial to this squad. Ravaged Base is your friend.