The 2 HD/level was from an older attempt at revamping the ranger class, which stopped at level 5 or 10 (it was meant as a beta).
I think a major part of what made some people feel that the Ranger was deficient was that many of its abilities had requirements that were practically unusable in actual gameplay. For example, Primeval Awareness seems like it'd be a good ability to sense what monsters are in the area, but it used up a spell slot and ONLY told you if they were within a mile in any direction. At least the revised version includes beast speech, and while it limits awareness to your favored enemies, it at least gives you a better indication of where to start tracking.
Hide in Plain Sight was another ability that seemed good on the surface, but then you realized that you had to spend 1 minute prepping everything, you needed material components, and then a solid vertical surface to stand against. The revision allows for greater flexibility and provides more opportunities to actually use the skill.