Being manaless is not always an advantage

For those who complain about champions like or or , which have no mana costs:

Having no mana does not always translate into an advantage. Yes, mana based champions are usually forced to itemize for mana or mana regeneration. This means that they can't buy pure damage during the early game. However, having no mana does not necessarily translate into an advantage.

Lets take Vlad, for example. Contrary to the popular belief, just because he has no mana, does not mean that he can freely spam his spells. He has costs... in form of health. Health costs are actually much worse than mana costs for a few reasons. Apart from the fact that you can't itemize for mana/mana regeneration items (you can, but these items are not efficient) - Because you are using a champion which sacrifices its health to cast spells, you are FORCED to build lifesteal/spellvamp/health regeneration to cover those costs. Vladimir, for example, is forced to buy a Hextech Revolver to cover his costs. He can't just build pure AP, his Q can't cover the costs from his W and his E unless Vladimir has 400 AP, and even then, it is better to have spellvamp so that the net health gain is higher. If you don't build some item that can cover those costs, expect to lose trades and die quickly because you are sacrificing your own health - so you are essentially killing yourself.

Another example: Zed. He can actually spam his spells during the early game. However, he can't do that to the same extent as Riven and Katarina can. This is because if he quickly spams all them, he can become out of energy quickly. Luckily during the early game, this is not a serious issue, as he can quickly recover energy. But as we all know, energy falls off late game compared to mana. Not only because you can be out of energy after one or two spell rotations, but also because there is nothing you can do to build more energy or energy regeneration.

Another obvious advantage of having no mana, but that applies to all manaless champions: as I explained above, you can't build mana or mana regeneration items. Well, you can. But you are wasting completely these attributes, so the item is much less gold AND slot efficient. For example, imagine if Vlad had mana. Rod of Ages would be the best item to build on him, and for good reason. While being manaless means that you don't have to build mana regeneration items to cover your costs, it also limits the amount of items that you can buy. Also, as I explained above, some manaless champions like Vlad actually have costs that are worse than mana and this also limits their build on the same way that a mana based champion has its build limited.

There are some champions who, in fact, have absolutely no drawbacks to their spells, apart from the cooldowns (and that can easily be solved by cooldown reduction, or resets). However, this is a problem with their design itself, not with the fact that they are manaless. Riven for example would certainly be more balanced if she actually had a limitation to her spell spamming. But just because she doesn't have that limitation, does not mean that every other manaless champion also has.