Outside of guild they are mostly hurting themself but in guild fotm reroller are a fucking cancer.
Rerolling is costing the guild a lot, i can understand why some people want to reroll but most of the time people wanting to reroll every tier are alwayse the same. They have a tendency to be selfish aHole, they're the one that alwayse find an excuse for being bottom of the metter, they feel the spec is to blame when most of the time it's just that they didn't invest time to learn/gear thier main specs. they alwayse put the blame on everyone but themself.
They ask for reroll and they expect to be treated like gift for guild cause they are rerolling to somthing more "powerfull", other player feels like they are getting cheated from it and they are cause the soak the minor upgrade out of everyone cause they are ungeared as fuck... 90% of the time they don't do better on thier new main anyway and proceed to start blaming it on gear/procs or any other BS excuse. Whenever you say no to them they react like they will alwayse say shit like "i do it for the guild" or "i thought the guild needed a ______"
From experience (witch doesn't mean a lot ) people who have ask for fotm reroll in my guild (outside of few exeption) were never player worth keeping. They alwayse were the first to quit whenever things don't go thier way. They were alwayse the one pushing for dps by failling mechanic, etc...
The rule in our guild is now if you want to reroll you need to bring the new caracter you want to reroll on as geared as your old one and you will be in the back od the line for trinkets or other very powerful upgrade...