Having a nuking-only playstyle is at its best in ep4, at its worst in ep2, and is situational in ep1 (meaning high mob-density quests like Wrath of Forest)
Sure, leveling might take longer without help for ep2 stuff. BUT! Once you're a high level (170+ probs), and have most of your attack techs at level 30, FOnewm nuking will be decent (at worse) in everything except in CCA, Tower, and Seabed.
Nuking is great for farming ep4 stuff, unsealing, and hunting stuff on lower difficulties, but I personally don't use it for anything else
TL:DR FOnewm is good for ep1 and ep4. If you want exp, make CCA rooms.