The reason the ex CFE aircraft have been deployed onto other BA routes is in order to reduce the capacity where there is insufficient demand. At the time of the switchover most of the EOG network (within range) was considered suitable for RJ ops, but of course there were insufficient aircraft for the desired deployment. At no point was there ever a suggestion that the RJ's be moved to CitiExpress in the regions because the need was greater at LGW.
Now it is possible that BA would decide to bring the RJ fleet under the auspices of CitiExpress whilst remaining at LGW, although that would beg the question as to why merge CFE in the first place. The other alternative would be to redeploy them if LGW was being wound down to a much greater extent than is already the case. Should that happen all options are open, but if not, then there would not appear to be any rationale behind moving them out to the regions.
Of course, that doesn't mean they're not stupid enough to do it...