hitman isn't weak imo

Hitman is not weak. It's terrible. It's the only perk deck that's actually worse than having no perk deck selected. The only time you can use hitman is if you're in an armor build (Rogue: 30% dodge. Hitman: 0 dodge). So that's off the table.

But the problem with armor+hitman is that you're sacrificing armor (what you need) for armor regen (which you don't). With Ace Bulletproof (from anyone on the team), ace die hard, and armorer, you get...what...like 1.5 second armor regen? With Hitman you get 1.1? Sacrificing 40 something armor for .4 seconds of armor regen is probably the absolute worst tradeoff imaginable. It wouldn't even be that bad if it allowed techforcers to continue tanking sniper shots without taking health damage, but it doesn't. By taking Hitman, you're allowing snipers to either insta-down you or at least hurt you where they couldn't before.

But, you also get akimbo without putting points in Fugitive. Well, big deal. When do you want akimbo? When you want a decent damage primary with high concealment. When do you want a primary with high damage and concealment? When you have Sneaky Bastard. When do you have Sneaky Bastard? When the akimbo skill is 4 points away. What other situation would you have sneaky bastard or low blow? When you're in a dodge build. When do you have a dodge build? When you're in Rogue (or crook if you want ballistic vests).

Hitman is absolutely, 100% awful. At no point is it worth using. Even if you just started the game and made the mistake of filling out Hitman first, you're better off using a blank perk deck. That's how bad it is.

Infiltrator, on the contrary, is actually a really good perk deck. If you go Techforcer with it gives 20% more health and armor (I think, not sure if the bonuses multiply or add up), combined with Underdog, you've got 35% more health and armor at almost all times (since you tend to be near a lot of enemies a lot of the time). And then when you melee, you regen health, reducing your dependence on first aid kits. With Walk in Closet, half decent accuracy, and a half decent weapon choice, a techforcer with Infiltrator simply isn't going down. Infiltrator is a fantastic choice if you don't want to go armorer or crew chief.

Now, all that said, if you like using Hitman, dude, fuckin go for it. Use whatever you want. You paid your money to play PD2, you don't need me telling you what skills or perks to use. Play the game and have fun.