While this is an Apple forum there is nothing special about a Mac or OS X that helps Premiere. Make sure your Premiere settings are using GPU assist on the Mercury playback engine. One solution is transcode everything to a lower-compression format, but that eats a lot of disk space. 2k DJI footage is very compressed and can be a bit sluggish even on a top-end iMac. If you have not already set the Premiere program monitor to 1/4 resolution, that is an easy step. However if you are familiar with Premiere it's best to stay with that because the learning curve to change is high. Premiere is especially CPU intensive and the playback engine is far less optimized than FCPX. The i7-3520M 2.90GHz with 8gb ram would help. H264 video editing is mostly CPU and GPU bound, plus 4GB is not much RAM. The MBP 13 would likely be a significant improvement, whether sufficient for your needs I don't know. Oh and unfortunately I need the mobility of a laptop. Would the mid-2012 i7 handle video editing from what I said above? Would there be such a difference from my current HP laptop? If not this one, which Macbook Pro would you suggest for something around what I'm looking for in terms of cost-benefit ratio? (I'm really not looking for an iMac performance but I want something at least better than now)

Here's a CPU benchmark comparing my current machine and the mid-2012.

They are willing to finance me a Macbook Pro and found one they could afford: a MacBook Pro 13' mid-2012 - Ivy Bridge i7-3520M 2.90GHz, 8gb ram ( these specs I guess - priced around 910 USD while a newer one is around 1500-2000 USD - my HP costed around 400 USD ). The playback while editing has been really bad - even though I can handle some laggy days and don't care about the final exporting time (I'm at Windows 10 using Premiere CC 2015 (plus Lumetri for coloring), exporting at 1080p, working with 1080p footage sometimes with some 2k from a DJI Phantom - the playback for the 2k footage is ridiculous)

Right now I'm doing some freelance jobs editing videos for a friend's video company using my 2014 HP laptop ( Haswell i5-4200U 1.60GHz, HD4400, 4gb ram - full specs here) and it's not been a good experience.

Best video editor for macbook