Leicester and Loughborough aren't exactly comparable. Leicester has the shopping centres and everything that Nottingham has, so people from Leicester don't really need to travel to Nottingham, for instance. Not so with Loughborough (in danger of losing its own indoor shopping centre, which is turning into a ghost town). It would be rather an inconvenience for passengers in places in between Loughborough and Derby.
It is worth noting that the section of the Skylink between Loughborough and Leicester was introduced last.
If I were to split the Skylink, I'd split it at Derby, with an express service running up the A6 between Leicester and Loughborough as present, then running down Ashby Road to pass Loughborough University, then running up the M1 straight to the Airport, then passing through Pegasus Business Park and terminating at East Midlands Gateway. (It could potentially then continue to Derby via the A50, A6, Wyvern Park and Pride Park.)
But on the whole, I think it's quite fine the way it is, and the most immediate change that needs to happen is to simply increase the capacity of the service, either through a frequency increase or larger buses.