I would add another vote for considering Bearded Theory..
Its on the end of May Bank Holiday weekend, probably ideal location wise and attracts a 'more mature' clientele which makes for a very friendly vibe..
I have been to the last few and until last year they had been blessed with decent weather..
Rock Werchter has always had a pretty diverse lineup. As mentioned before, in the last 10 years you've had Dua Lipa, Stormzy, Oscar and the Wolf, Pink, The Chainsmokers, Macklemore, Ellie Goulding, Pharrell Williams and more playing in prominent spots. I'm not sure you'd get them playing Download or Rock Im Park anytime soon.
I'm not sure this year represents such a radical change in direction or genre for Rock Werchter as you've suggested. We've only got maybe ~25% of the total lineup announced so far? This seems premature to be making statements bemoaning about how the festivals changed when we don't know what most the acts will be yet!
If you're interested in going to a more narrowly rock focused festival, then there are plenty of other festivals this summer catering to that market like Download, Rock Im Park, Rock For People, etc. I'm not sure Werchter is, or ever really has been, exclusively a rock festival in the same way as these other festivals mentioned above.