The whole exercise is not about what the RN is likely to do, but what it should do. And the spec wasn't "replace a frigate" either. The voting brought out three significant requirements, and ultimately got distilled down to a displacement bracket of 8,000-10,000. If you desperately want to design under-armed OPVs then cool, start a thread on it, but this is a committee exercise and if people voted for stuff you don't agree with well tough titty.
Back to assessing the feasibility of a 10,000 ton through-deck design here's a rough-scale view. The hanger is only about big enough for 3 EH-101s but could probably handle 2 EH-101s and 2 Lynx/NH-90s etc.
The CIWS are Skyguard (FCR/Optics mounted on superstructure, front and back). The VLS is extended-depth Sylver with 64 cells for a mixed load of TacTom, SM-3 and SAMs (I'd go for Aster and treat SM-3 as an add-on load for the combat systems).
The propulsion is 3 x RR waterjets with all-electric drive from a CODAG power unit with exhaust venting at rear port-side (TAS rear starboard-side). Ships launches would be on starboard side as would aircraft workshop.
