She is NO DOUBT a good unit. The reasons why gellius is often used instat of deine by quiet a lot players who have both is simply that deines UP costs are crazy high compared to gellius and pure tanking with 5/5 skill for gellius he just straight out wins (the down time on the skill is realy low), especialy if the tank also has to take some magic damage on the way. So if your looking for a pure tank gellius is your man, but deine can do the job too AND smash her enemys face. We are not as advanced yet in nutaku version that we would REALY need gellius tanking over deines tanking, its most often just easier to deploy gellius if u just need a tank.