AP and Stamina (and Defense) are pretty much the only gear stats that matter (as I’m pretty sure we’re both aware). Haste and Crit values from gear are pretty much always laughable, even on a fresh piece of gear designed for it, and they become especially laughable at high levels when you have access to the really good perks and mastery benefits (1% Haste and/or 1% Crit from gear doesn’t really mean much when you’re already getting a passive ~20-25% in both categories from perks; it gets even worse when you factor in buffs which further render those stats irrelevant due to their size and straight additive nature).
At level 30, with all perks/masteries and all beast perks, a naked Garrison has 4193 hp and 11444 AP. In his best gear loadout (Cursed Blade + Possessed, High Paladin Armor + Unholy Might, Skysteel Band, Pulsing Demon Heart, Battlemaster’s SoV; all legendary), he’s got 9293 hp and 18658 AP. That’s 222% of base hp and 163% of base AP, on top of Invigorate. For my 'Bretto, naked, he’s got 11318 hp and 4695 AP; geared up fully (Calamity + Possessed, Star-Forged Plating + Unholy Might, Skysteel Band, Cold Iron Chain, Frozen Stone; all leg), he’s got 16958 hp and 11175 AP, which is 150% base hp and 238% base AP (I actually use Overcharged Cannon for my 'Bretto, which is about 2224 less AP in exchange for Invigorate; I consider this more useful since I’m already overhealing like crazy with 'Bretto and Invigorate allows me to just chain cast Nature’s Wrath and Cleansing Rain without interruption). The differences become even more stark when you factor in defense too (gear tends to more than double that as well).
The biggest effects of level come from perks (which aren’t really level dependent; if you spend all of your time fishing, you can max out perks at level 10 when you get to the fishmonger), the ability to equip better gear (every 3-4 levels, the stats you’ll get from a given slot increase by ~50%), and level modifiers in the damage equations (this is the biggest effect of leveling).
Of course, it’s probably important what rank the gear in question is and whether it’s enchanted up correctly. Legendary gear with legendary enchants that are level appropriate are a world of difference compared to green gear that’s unenchanted. If you’re used to running with unenchanted greens, I can see how you’d see level as being more important than gear.