S4C sent out press release about their relaunched website on Thursday. The fact that they also changed their logo and idents is only mentioned in passing, they apparently didn't feel it was that important.
S4C have been criticised in the past for their lack of digital innovation although it was never about their main website, more about on-demand service, availability of programming on other services. Some production companies were slow to look at support programmes with websites and apps but they've caught up fast.
So it seems to that they wanted to emphasise their website redesign, even though it's evolutionary not revolutionary. They've used the same technology for 15 years, which is fine, and are just re-skinning it. There is a bigger redesign for Clic but there is no real innovation in the actual service. (I don't think adding social media links count).
The re-branding was done by Sugar Creative and from
their website it sounds like they handed over to S4C's internal team for applying to the website, as well as production of the idents. That might explain the lack of creative vision there.