I build my models with as thin a T.E. as the material I'm using will allow without splintering, and within the design parameters of the full-scale I'm modelling (no razor sharp edges on a WWI, etc). The thinner the edge, the less drag. Flutter prevention can be addressed other ways, like no play in the control linkages, sealing the hinge gaps, adaequate stiffness of the control surface, and proper shaping of the LEADING edge of the control surface, where induced turbulence due to the change in surface (wide hinge gap) and disrupted boundary flow can induce flutter over the control surface.

Hangar rash can be a problem, beating up thin T.E.'s. I harden the edges of my control surfaces with thin Ca after careful sanding to the final thickness. It doesn't guarantee no damage, but what would otherwise be a definite ding and dent just becomes a small tear in the cover, or other more easily repaired boo-boo.

There's some nice stuff becoming more and more popular for skinning material (or maybe I learned about it after everybody else )
G-10 fiberglass in assorted thicknesses. I only wish you could get it in corrugated panels for certain scale aileron applications. You can really get thin T.E.'s and maintain a good strength to the control surface.