Absolutely. If you want top-tier results, you'll have to hire top-tier people and I don't know a single "designer" who's great at every aspect of design and front-end development. It's important to realise that great design is a balancing act between all these aspects and to ensure your team manages them, e.g. a designer designing isolated from the front-end developers.

If you're not hiring employees, but are relying on freelancers, I question just how reasonable it is to have a designer use your templating languages and other tools instead of standard ones such as plain HTML and CSS. There are exceptions though: things like Wordpress and jQuery are common enough that you can easily find freelancers who'll be able to use them (but they're not common enough that every freelancer will).

This is where a lot of the problems come from. To many "designers" think that they're also usability experts and information architects. The main problem comes from the fact that those disciplines can be subjective in their nature. A lot of decision making in those roles is about personal "opinion" as in; "Well, I think the search box should sit in the top-left corner of the page". What's easier than stating your opinion? And we all love doing that. A lot of employers simply do not understand this.

Actually to few designers do ux and vice versa.

Did you meant to say; Few designers "understand" ux and vica vera?