Obviously I'm not on the ground down there, but some of what I have been hearing suggests Epsilon has not been the runaway success ICG have been suggesting (ICG do need to impress their shareholders afterall). Certainly she allows IF to compete on frequency with Stena, but do her carryings between Wales and Ireland justify significant investment in either replacing her or upgrading her (which may be easier said than done). Speaking to those "lucky" enough to travel in her she would appear to compare very unfavourably from a passenger perspective to Ulysees, and also Stena Adventurer and one would also assume Stena Superfast X (and some even say Stena Nordica) Personally I feel her future lies as a replacement for the oldest ship in the fleet - Oscar Wilde. She is ideal for the French run IMHO in that she can shift a lot of freight very efficiently with ample space for those all important trade cars. Being a Visentini she should also be relatively straight forward to upgrade with scrubbers, etc and it puts IF on a similar cost base to Stena - Oscar cannot be a cheap ship to run.
As for the central corridor, perhaps something will be displaced from the Baltic which could be made suitable. Unless they where to build (and possibly even if they did build) in the far-East any new build would be prohibitively expensive, and the uncertainty regarding the future of the industry in relation to upcoming legislation and the slow return on investment means raising the capital could be problematic - ask Britanny Ferries! Yard space isn't easy to come by either these days with cruise and cargo ships filling up order books for the next few years in just about every European yard capable of building a large ferry. What could be made suitable? Well that's a tricky question - Stena's success with the Superfasts up here and the conversions for Marine Atlantic show that anything is possible with the right team in place. Personaly I wouldn't be surprised to see Isle of Inishmore move North again and any new acquisition be placed on the Pembroke run so IF can go toe to toe with Stena on the premier run. I'm still not convinced the swift's future is secure either, particularly if passenger capacity is increased in the conventional tonnage. Whatever happens, there's going to be a big increase in passenger capacity compared to just a couple of years ago meaning things could get very interesting! I also wouldn't be surprised if Stena have a surprise hand to play either.