If you think about it, WotR actually also has an epic start. You personally are just a wounded nobody, but you see a demon lord behead a silver dragon and witness a demonic invasion within the first thirty minutes. But I have never seen anyone accuse WotR of feeling too epic off the bat.
I bought WOTR upon release last year, played it for two weeks during my holidays -- and I haven't yet picked it up since. One reason for that is that Owlcat REALLY love to have tons of combat to the degree that they just put trash mobs on like every spot on their maps that appears empty (to exaggerate).
The other is that I prefered Kingmaker that way, the much more grounded beginning in particular. It's not only that WOTR starts with a demon invasion. It turns into a power fantasy creep almost immediately, both mechanically as well as plot-wise (you're being "gifted" mythical powers right in the first dungeon). You can't fault the game naturally, as that's the selling point of the Adventure Path this is based upon. Eventually I'll get back to it. It's a good game. But back then, it was a bit "much". And I was stuffed.
Re: Combat pacing, that's one thing Larian will likely get much better than in WOTR (or Kingmaker, or their DOS games). Based on the EA back from two years anyway.
For one: Direct combat isn't the only option. Secondly, whilst Larian's maps are highly condensed affairs, with druid groves sitting right next to goblin camps sitting right next to dangerously dangerous dungeons: Not every single path to every destination is stuffed with enemy mobs, acting as roadblocks from A to B (as tends to be the case in Owlcat games -- or DOS). And lastly, back in the EA, even depending on the race you chose, you could avoid turning NPCs otherwise hostile from the get go.
