But I need to start looking at this as a potential business, if I want to survive while working on games full-time - and if smooth movement brings a lot of players to the game, then I will, of course, consider it
Dungeon crawlers have been a niche for a long time, whether you have smooth movement or not, the change in audience will be miniscule.
I take that as a personal offense. Lo, there I see Grimoire, Grimrock II many Total Conversions, Ruzar: The Life Stone, Heroes of Monkey Tavern, The Seven Mages, Operencia, The Quest, Vaporum I+II, The Fall of Dungeon Guardians, Tower of Mask, Dungeon of Dragon Knight, Islands of Caliph, Aeon of Sands, StarCrawlers + Chimera, Dungeon Kingdom (probably won't ever leave EA, but it's like 99% finished, just not optimized 100%), Legends of Amberland I+II, Heroes X, and now even Mystic Land joining the fabled queue, bidding welcome to many a player with outstretched hands!