Maybe I'm just dense here, but I've been playing D&D in all of its incarnations for 22+ years, and I don't see, at ALL, how 4E is noticeably more "combat-focused" than any previous version.
Can someone explain, with specifics?
Not to be too snarky, but they're right above. This page, the previous page...lots of details about how 4e's material is, speaking in focus, on combat, in the core rules.
They do address other things, but every class power, every monster in the MM, and most of the words about set-up, encounter design, and rewards in the DMG, are about
combat. The four roles are combat roles. Rituals aren't spells because spells are for combat. You don't have class/profession skills because they have no use in combat. The rogue is a ninja because it needs combat balance. Healing surges exist so that there can be more combats. Play sessions are combats chained together through dialogue. An encounter is either a combat or a skill-based combat (and the skill-based combat has mechanical problems pointed out elsewhere on the boards).
Perhaps the strongest case, the one that sold me, was that the roles were once "dungeon exploration" roles (trap guy, swiss-army-knife guy, fighting guy, recovery guy), and now they're expressly "combat" roles (fast guy, healing guy, crowd-control guy, damage absorbing guy).
It can be (and has been) vastly overstated before, but I'm beginning to get why this impression is there. It is there because, yeah, combat is a bigger part of what the game is about in 4e. Even though it was always a huge part of what the game was about, it was never the ultimate end point, just an important part of getting to that end point. Now, it seems to be the endpoint. Everything is cleaned up and refined around that purpose.
For many critics, that is all well and good, but it leaves the parts of the game that the liked (exploration, for instance) by the wayside.