I drive an awd 300 with the detuned v6, it has lower torque output than your turbo 4. We all know it is toque we feel getting off the line. I feel my car has very adequate power taking off from stops and lights, awd also makes my car slightly heavier. So your car makes more peak torque, is lighter and is supposed to be blessed by its 8 speed transmission. It must do equal or better than my car off the line.
I own a 2002 Subaru wrx, I’m new around here, Subaru wrx driver since 2006. Those turbo 2L engines are laggy off the line and do require knowing how to apply throttle, can’t just stab the gas pedal. The other thing I’ve learned is that turbo engines have a lot of plumbing and vacuum leaks can cause a big headache. Sounds like you are not the original car owner nor know the service history. I think you said the car has 70,000 miles, have you looked at what service your car requires at 60,000 miles ? Try to get your car service all up to date, you may find the issue while at it. I can tell turbo Subarus get unhappy from something as simple as the air box not been properly sealed. I spray clean the maf every other oil change and check the air filters every oil change. If your car wastegate is not working properly it’ll definitely cause driveability problems. Curious to hear what the fix will turn out to be, I was considering a 2017 300 rwd before I found and purchased my 2017 300awd.
Good luck.

 

So guys I have an update, sorry for the delay. So turns out the spark plugs were fried basically, and also fuel injectors worn out. After fixing these, the car seems 95% better in performance. I still feel like theres some very slight gallop when i accelerate hard, but maybe its just the bad tire wear or treading. Will mostly have tires replaced within next few months. Thanks everyone for all your help.