What affect does wrong level gear have?

[Physic]

It's a hidden stat reduction, but unless you're using a parser to get your exact numbers, to be honest the reduction will be hardly noticeable. Damage calculation, like enmity calculation, is so overly complicated the only stats that really matter are VIT for max HP and INT for max MP.

SE is simplifying enmity calculation. Let's hope they simplify damage calculation in the same way so stats begin to make sense.

not really true, its generally pretty noticeable, especially the accuracy drops, and even the attack.

You can check by comparing how the stats change when you look in your actual attributes, not the the red and green or whatever colored stuff, but the other window that shows accuracy defense etc. if its a stat that isnt on that list, your guess is as good as anyones, but in general your are always better off using something optimal, unless its really outdated, the +5 is usually good, but sometimes there are big stat jumps with one level.

wearing anything non favored is almost always crappy.

[Eekiki]

not really true, its generally pretty noticeable, especially the accuracy drops, and even the attack.

You can check by comparing how the stats change when you look in your actual attributes, not the the red and green or whatever colored stuff, but the other window that shows accuracy defense etc. if its a stat that isnt on that list, your guess is as good as anyones, but in general your are always better off using something optimal, unless its really outdated, the +5 is usually good, but sometimes there are big stat jumps with one level.

wearing anything non favored is almost always crappy.

Then what to the stars do on the +1 equipment, huh? HUH?! Bet you can't answer that, Mr. Smarty Smart Smart!