Here's a guess at how our 3-3-5 defense would look like....
DE - Bobby Greenwood - 6-5/270
NG - Terrence Cody - 6-5/380
DE - Lorenzo Washington - 6-5/275
LB - Chavis Williams - 6-4/220
LB - Rolando McClain - 6-4/249
LB - Jerrell Harris - 6-3/215
CB - Kareem Jackson - 5-11/192
FS - Rashad Johnson - 6-0/190
SS - Justin Woodall - 6-2/220
NB - Javier Arenas - 5-9/198
CB - Marquis Johnson - 5-11/192
That's not a heavy defensive unit and I think would it do well against a spread offense. The line is a little heavy but it is needed to pressure the QB. McClain behind Cody would stop a lot of draws up the middle while Harris and Williams are fast enough to run down any QB trying to scramble.
I don't see what the concern is about.