LCY was never really intended to be a transit airport, although as both BA and CityJet (AF) have a significant network there some people will end up connecting.
It's point to point where LCY really shines, you can check in very close to departure and on arrival luggage is very quick (if you've checked bags) and it's only a few minutes walk to the taxi rank and DLR.
A proper lounge may not be feasible as I'm sure there's a higher percentage of elites in all alliances compared to the larger airports, LCY is particularly geared up to the short haul business traveller - and with the CWLCY service even some of the longer haul.