I don't see why custom maps would kill the last servers...
You answered yourself in next paragraph. But to add to that - not many players will download their autopatcher (as it unfortunately was the case with mumble - this community is too lazy) and people won't get custom maps automatically what will result in massive disconnects. And even if maps will be of worse quality than stock maps, people will have to download them if they want to play any FH2 because there is only one server left. I'm afraid they will be server killers. Custom maps may be fun on some events but not on everyday play, so let's hope it will be some event. Anyway, I can understand people making maps for tournaments, because gameplay differs much very often but if there are any talented mappers there, why they don't apply to FH2 team? With help of experienced mappers and testers many custom maps could be so awesome... but they don't.
Last Fan Mappack to 0.7 was brilliant. Shame no server ran those maps for more than couple of days and in special occasions because nobody had downloaded them.
Stashuv Area, Soletschnogorsk and whatever_it_was_called_PHL_0.7_version were my definite favorites. Also Cretan Village was fantastic.
This was actually the only good quality fan mappack (Cretan Village and Todtenbruch are my favourite FH maps even nowadays) but most of the custom maps are unfortunately badly designed. Afaik maps in Forgotten Hope Fan Mappack no 6. were made in cooperation with FH devs (and released via FH main page) by people like Lili Marlene, Knoffhoff, Mr_Cheese and few other who were future FH2 devs.
Well fan maps can be fun. I always think there are a bunch of maps that deserve to be tested out by the community to see how they play on a public server (it's a great way to do some quick stress testing). I think a lot of 'diamonds in the rough' can be found this way and improved upon.
I have nothing against it, but problem is that no one has time to polish those diamonds and original mappers usually don't cooperate, because they act like their work is perfect, they ignore feedback, don't accept criticism or simply don't care anymore and move to other projects.