This is kinda true, but something to keep in mind is that you want a good balance between crit and hate, I would rather have 150hateinc 150crit then 300hateinc and 0 crit. So go for pieces that have both, dont stare at hateinc all the way. On my main guardian the legendary rings and t6 gear push me to around 27% hate and 22% crit, which is massive. But you're quite an aggrobeast already at 18% crit/hateinc.
Regarding hitrating, guardians is the class that requires least hitrating of all. From my own experience the innate hate from shieldslam goes trough even if your target parries the combofinisher. Could be tested pretty easily
Just run with Pressing strikes and you should be fine, theres some nice faction-dps rings from khitai with good crit and hitrating.
Whenever im starting a baby guard, it doesnt take alot of gear before i can compete with well geared conqs and guards, so you are right about that, you just need a decent weapon, redpoo wrote nice pieces to strive for.
something thats obvious to most, but maybe not for you as a rather new player, is to preload shieldslam if the situation allows. If someone is pulling the boss from far away you wanna start the finisher of shieldslam as soon as the boss is in your vicinity. It gives you stronger initialaggro and you will have it off cd sooner, which means you will be one shieldslam ahead of other guardians for the whole fight, makes a massive diffrence