Losing interest with my Sniper

I would say slow down the pace if you're getting bored, try another character maybe for some variety - every time I play a level 2x it reminds me about how far I've gotten since then. But with all the new low level content Nexon continues to add, sometimes it's worth it to start over just so you can experience it at the right level. Plus a decent number of quest rewards are low level, if you just train to 40 you can get 30-40mil of rewards pretty easily (especially with a high level character on backup for more difficult etc. drops).