I don't think it's a good idea to start giving enormous bonuses for high level retirement right away. Better lure those that want to retire first, then slowly increase the gifts to get more people to do it without giving tons of LP.
Maybe, but most high lvl's went gen16 before stopping retiring, and with 15 looms you can have: Helmet, armour, greaves, gloves and a shiney weapon. Many high levels have also had plenty of gold to shop with, so a shield, a crossbow, bolts. Who needs more than that?
The incentive to go high level will always be more than that for looms, I BELIEVE anyway, since once you have a set theres no point in NOT being as effective a char as possible, and even lvl 32 is a massive advantage, thats 6 skillpoints, you could make your hoplite a lancer, or your 2hander a 18/24 build with so much more surviveability.