Couldn't agree more. LCY caters for the richer folk living this side of London, even on bucket and spade routes, who don't want the STN - FR / EZY experience and can afford the premium.
STN remains much easier to get to than SEN. The A12 out of London is often a nightmare and the train takes longer than to STN. If EZY gets the fares right though it could be fine. I'd try it for the novelty value alone and the fact that it'll be quieter than STN. And anywhere but Luton I'm afraid.