i think putting naganadel in A is largely overselling it. the only viable set it can run is tailwind, and while its decent, its really frail and relies on focus sash to get tailwind up most of the time, unlike mega mence which is a much better tailwind user. tailwind is cool, but its not like its a niche that most teams need, and mega mence can at least run other sets that are viable unlike naganadel. also, since its forced to run tailwind and protect and usually runs sludge bomb as its only stab, it has to pick between either flamethrower or hp ground for its coverage move, which either renders it useless against heatran it if picks flamethrower or celesteela and ferrothorn if it picks hp ground. i feel the only reason why you'd really need naganadel on a team would be if you already decided to build around a mega evolution so you couldn't use mega mence but you really needed an offensive tailwind user instead of something like suicune, and while it does a decent job at doing this, this niche is not worth A rank to me.
i personally wouldn't put it higher than B+, in smogon's viability ranking it's ranked B and i definitely agree with that ranking but i wouldnt be opposed to it being B+ i guess.
i personally wouldn't put it higher than B+, in smogon's viability ranking it's ranked B and i definitely agree with that ranking but i wouldnt be opposed to it being B+ i guess.