You're building a strawman. We can't expect democracy after Putin is gone, but we can't also expect the same situation we're in now. Putin was an exceptionally strong leader, but part of that role is pruning all possible strong competitors, which usually means that a weak leader will succeed him. The good thing about weak leaders is that it's difficult (and personally risky) for them to mobilize a country for a new war, even if they're more psycho than Putin. As you say, Putin has a lot of support, a new random person will not just magically inherit it just because they're now the president.