Yes, well, you're right of course, and here's why. Presenting a little breakdown of things when you fight solo. Sorry if it's a bit long...
Strength adds 1% damage per 4 points; that means enemies survive 1/1.01 the time so inflict that much damage (on average). The benefit of, say, 100 points of strength, is to reduce the damage you take by 20%. This would be useful if you were fighting in a group, but solo it is almost entirely useless.
Vitality adds 10 hp and 1hp/h per 1 point. While you don't take less damage in combat, you can say the damage is "diluted", it's exactly the same as taking less damage. Starting at 10 points (for warriors), every 10 points dilutes damage further. To take 20% less damage, you need a mere 2.5 extra points of vitality - at first. After that, it gets less useful. When you have 400 health, for instance, another 10 points of vitality are needed to reduce damage by 20%. And so on.
Dexterity behaves quite differently with higher- and lower-level enemies. Lower level enemies almost never have enough Agility to withstand the level modifiers, so Dexterity has little use against them. Against powerful opponents, though, that same level modifier makes Dexterity essential. Where an 80% to-hit chance could turn into 50%, 120% chance turns into 75% - essentially raising damage by 50% so reducing damage taken by 33%. The more agile the enemy, the higher the return on this. At minimum this is 1% per point of Dexterity, right up to the point where you always hit - which is never the case with truly tough enemies. Contrast with Strength which gives 1%/4 points, at best.
Agility is by far the most useful property of all. Against strong enemies, it both gives some chance to evade (similar to dexterity gains, but this time reducing damage rather than ensuring a hit - which is more useful when solo), as well as increasing Block chances. Unlike Strength and Vitality, and unlike Dexterity, the more you have of it the better, with the ceiling set at 25% enemy to-hit. Like Dexterity, this is almost never reached against higher-level opponents; it allows Rangers to fight tough enemies on even terms while rendering lower-level enemies completely helpless. Of all other attributes, only Vitality stands to any competition at all with this attribute, and only in the first levels - then the benefits of maxing Vitality sharply decline, whereas Agility remains a strong investment. At the same time, Rangers can still increase their fledgling Vitality and receive good benefits from the first few points, without needing the
Intelligence, I don't even want to discuss. Almost the only thing it does is provide Spirit; the experience bonus is nice, but not only does it not work with items currently, it also doesn't seem to compensate for the lack of Dexterity or Vitality, at least not in the earlier levels. It may become more important later on - or it might not. Personally I'm betting Agility and Dexterity will remain the most important attributes in all 5 Tiers, assuming the mechanics isn't changed. The Mystic's dependence on Spirit requiring high Intelligence is a handicap, not a bonus.
Bottom line: Warriors and Mystics have 1 good attribute; Rangers have two, plus they can still take Vitality in the later stages and not miss on much. Almost all my items give either Vitality or Agility, with a few to Dexterity. The Strength items I really should get rid of; I've already been rejecting items that give strength in favor of weaker items with Agility, because it's the only way to actually survive battles.
In the later stages of the game, one of two things will invariably have to happen. Either same-level opponents always hit you and you always miss them, if you're not a ranger; or the opposite happens if you are a ranger. That is because, when rangers have 120 Agi and Dex, the Warriors would still have around 30-40 at best - an 80-point difference that renders all encounters either too easy for the Ranger, or too difficult for the Warrior. The "equalizer" here is level difference modifier - which means that Rangers will forever fight enemies of higher levels than the Warriors.