"Clan tactics" can be as much a curse as a blessing. For one, although the index kinda already does it for at least some of them, you're limited to special chars from that clan. And from what I can see some clans have exactly zero special characters of their own, who knows if that'll get remedied or not. Probably not. And if you look at the likes of Space Marines, CTs don't exactly tend to be equal in power level. And then you'll end up with either playing a substandard CT for your painted army or using incorrectly painted models for a better CT. Personally I'm painting my orks in a custom scheme (a first for any of my armies so far), so I can be whatever CT I choose I guess because it's not a "canon" clan. But even that feels kinda "meh" as a "solution."
I don't care about Special Characters at all. As long as the clan traits are useful or at least fun I'll pick one. Or I'll pick none at all.
I can't say you really need to worry too much about how you paint your orks as far as picking a clan goes. MY goffs tend to have a lot of red on them as a kinda throwback to 2nd edition goffs. I prefer not to use yellow on my glash gits, I can't recall if they are suppose to be bad moons or just pirate outcasts. Mine are free booters from the deff Skulls. I was looking for a way to add blue to my pallet. Remember there are clans and tribes so there can be a mix. Which will probably be done via detachments with the new rules.