I'd agree - have used Luton a few times over the last year even though it's far from my regular airports and on all occasions, it's been absolutely fine. One of the better ones.
The plan to mothball T1 at Manchester is driven pretty much entirely by the new DFT security rules and the cost of upgrading T1 security to meet the new standards - not to mention the increase in staffing that you need for teh new procedures as well. If you're going to decommission it at some point anyway, it makes absolute sense not to spend millions and millions on an upgrade to a facility which will be in use only for a year or two at most. You put as much throughput as possible through T2, turn T3 into a more lo-co facility and leave T1 exactly where it is, although there is the possibility of using some of the T1 pier stands which are connected through T3.