The idea behind Wobbuffet being excluded is entirely because of his movepool, stats, and ability. His typing has nothing to do with it. Essentially, he receives an ability that does not allow the enemy to retreat, has enough of defense and an outstanding max HP (584!) HP to survive at typically several attacks, can lock an enemy into using the same attack several turns with, and learns counter and mirror coat, and destiny bond. This means that in virtually every situation, he is able to faint at least two Pokemon.
I don't know much about Spiritomb, I only assume that the moves it had were bred onto it, and that both attacks have 40 base power (however, typing makes them 60, with the 1.5 bonus, and Pursuit can also double if used strategically). Psychic, Fighting, and Normal attacks cannot even affect Spiritomb from his typing, and all other moves are of normal effectiveness or worse, which is where his advantage is.
Actually, I looked at it on serebii.net just now, and though, like I said, I don't know much, I have to say that it does seem to have a very advantageous move pool, allowing it to survive a lot of attacks. It's base stats are average when compared to other high-quality Pokemon, but it's speed basically means that it will never attack first without an attack allowing it to strike first, which it does learn a few. HP is also a little lower than average, but not by too much.
All of that said, I know that Wobuffet is typically banned from all serious competition, just like several of the legendaries you posted are. I haven't ever played in one, but I've read several times from credible sources that he is "uber" along the lines of Mewtwo and Kyogre. The idea is that while Wobuffet's movepool is almost entirely predictable in every circumstance, there is no way around the opponent losing out to him, since counter and mirror coat do double damage as what is done to him. In fact, looking now, Spiritomb and Sableye seem to be the only things that were made precisely to put him away. However, remember that because of Wobbuffet's ability, you wouldn't be able to switch to either one until after you lost the Pokemon you were using.
But all in all, I'm comfortable with leaving them both out, that's fine with me. I'm posting mostly out of concern of what I have read about Wobbuffet. I know that the newest generation hasn't been explored very well, and I recognize that Spiritomb has been able to do large damage competitively w/o me knowing anything special about him, so he may be too strong for balanced battling, or at least for battlers who do not yet have a middle-to-large variety of Pokemon to be prepared for this. My recommendation is to ban Wobbuffet definitely, and to seek out someone who knows a dime about battling to decide whether or not to ban Spiritomb. If you don't feel like doing that, go ahead and ban him. I'd rather play definitely be balanced than having it be tilted to one side.
I'll tell you now that Spiritomb may be on my team as time passes if you do not ban it. I don't have any counters to Psychic pokemon at this time, and he would be the first pick for me, so if you absolutely don't want to see it, ban it, and I'll forget about using him, probably passing it up for a Weavile or something like that, if I do decide to use him. Just letting you know it is a strong possibility.