bmi indeed has a very attractive and eye-catching livery, which I think will help to establish the airline quickly in the new Middle Eastern market. The only problem as I see it, is the name. bmi, despite having the union flag on the tailfin, does not sound very British, and I agree that a move back to British Midland would do a lot of reestablish the airline. Not only would it reestablish the airline in the UK where it is mostly still referred to as British Midland, but abroad the airline would have a fierce sense of nationality, which I think particularly for a longhaul airline is very important.
I strongly think that this merger, alongside the drop of CDG, will be the first in a series of steps to get rid of the shorthaul network out of LHR. bmi know that mainline is being attacked at all angles by more efficient competition. That could be British Airways providing a full-service product and extensive route network. It could be easyJet or Ryanair flying from local airports with much lower cost bases. Or it could be the train, who profit from it's hassle-free city-to-city option, and it's current green image. Yields have become so eroded in bmi's traditional shorthaul markets, that I'm sure as soon as bmi have the resources and licenses, the airline will move swiftly to more medium and obscure longhaul markets.
It could also spell the beginning of warmer relations between British Airways and bmi. BA and bmi already offer passengers the opportunity to fly from Saudi Arabia to London, and then onwards, with just one ticket. BA also offers members of Executive Club to rack up air miles and tier points on bmi's Saudi flights. I can imagine BA would not like to lose the through traffic from these important markets, and would be keen for bmi to codeshare and offer through traffic from October when the franchise ends. Purely from an observer's perspective, this could work well to get bmi off of the domestic feed routes, BA operating these instead (obviously bmi keeping their slots).
I can't see bmi merging any members of the group into one umbrella brand any time soon, sadly. bmibaby has established itself north of the M25, with a visible and popular brand. The airline may well be chronically underfunded and shy of the competition, but in the markets where we are now, we're often a key player. I wouldn't be surprised to see bmibaby sold however, because it's clear that bmi are no longer interested in serving the kinds of routes that bmibaby do, and perhaps might find the baby brand dilutes that of mainline. bmi regional will have a very successful future simply doing what Midland had been doing for years, finding a niche market and providing an excellent product to attract returning customers.