I would be really surprised if it was IF. I've never heard anybody say anything bad about them in regards to touring.
I had a listen to the two songs you posted... did not expect Heafy to have adopted a James Hetfield style of clean vocal
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sounds OK, although I don't think his singing has ever been great, just passable. Honestly I prefer his harsh vocals on The Defiant to how he sounds on ETI and Ascendancy. They still aren't particularly good but they sound a lot more controlled. Defiant is a pretty good track actually, sounds closer to MDM style than a lot of the stuff on ETI & Ascendancy, which always gave me a more 80s thrash metal vibe than MDM.
The biggest problem I had with Trivium at the time (and still do to some degree) is that they are very much a product of the hype machine. I remember them being advertised everywhere practically from day one. They got a lot of attention despite the vocals being pretty bad and the guitar work being good but not as good as other bands who didn't get the same attention from the media. Ascendancy is a good album but it's not
that good. There are some nice riffs and solos but a lot of it feels like a best-of 80s thrash compilation, and as aforementioned the vocals just aren't good at all, objectively speaking. Absolutely nothing against Matt Heafy but during that time period he was like a budget version of Corey Taylor or the Shadows Fall vocalist.
Since then Trivium have experimented a lot and worked hard, so fair play to them. I have nothing against the band, they have just never really been my cup of tea and I never understood the comparisons between them and MDM bands, other than the screaming which was more like Slipknot and general metalcore than MDM.