Ok, this is long so before reading it, keep in mind that my solution is the exact same as the accepted solution, this whole thing is just my though process and reasons for such buff, the reason i didn't write up earlier is 'cause i wanted to give it a week to make sure to not be rushing any thoughs, just found out that the answer was already said
Ok, i gotta say, when the evo shields were being announced my brain started going throgh a lot of how exactly every detail would work, and the most important questions were how much health it had on lv 2 and 3 (that got answered by respawn) and if the extra health would be added to your health. when they said that no, it just added empty extra health slots i was rather exceptical about the whole deal but decided to at least give it a shot and see how it played out.
As basicaly everyone that played the mode can say, it was lacking to say the least, if 50 health of a white shield weren't a dissapointing enough landing reward, making it only 25 while the guy 2 buildings down the street gets a golden one, wasn't exactly better. but granted, once this is in normal matches that wouldn't be an issue, it still falls apart even when compared to a regular shield, considering that you will normally need to get the drop on someone to get it to lv 2, which is hard enough by being in a stright dissadvantage health, you don't get and inmediate reward, since you have to disengage, get to cover and use your healing supplies just to break even with a white shield, you have to put not only the intended risk of engaging while low on health, you have to take time out of the fight and spend extra supplies, all of this means that even if you pulled of the assasination flawlessly and got away without getting touched, you would have to leave the fight and your advantage just to be in even terms with someone that has minimum gear, it's just not whorth it, and the lv 2 shield suffers from similar problems since your would be running around with this around midgame.
Yes, it definely needs a buff before going into normal mode, but whatever you do with it, keep in mind that a lv 3 is a straight upgrade from a purple shield and a lv 4 is a sidegrade to the golden one, so if you buff it too hard, the upper lvs would be too strong, as such, a minor buff that helps mainly the lower lvs would be to simply make the gained shield space be filled, efectively adding 25-50 to your health mid fight, taking away the time and supplies problem and wouldn't be game breaking in any way since, at the end of the day, unless you were to be facing a guy that has a lv 3 that is at 10 health and you have your last shot in the mag and he pops lv 4 in your face to finish you of with 25 hp left, the only thing this is allowing your enemy is to not be in a direct dissadvantage to you