Monitors vs dell outlet vs gaming question

Hi there,

Question:
assuming I'm running a single gtx1070 founders without OC-ing the gpu, 16gb ram 6700k.
With primary monitor: Dell U2312HM plugged into the HDMI port via DVI/HDMI converter. I "believe" i am called "gaming on a 1080" (tough to work on the lingo)

Secondary monitor: random 22nd Dell monitor from 5 years+ ago plugged in through DVI

The gaming is all done on the primary monitor only, the secondary monitor is used to just play videos/movies while I game. So no, I do not plan on using both screens to game "at the same time"

My questions are:

1. Seems like I am not 'making the best use' of the gtx 1070. Sure I am getting 200+ FPS on dota (less in game, but still WAY better than before) and I'm maxing out everying on WoW, but seems like i'm not making the most out of it, is that correct?

2. If the above is correct, what adjustment would I benefit from making? Bigger monitor size? "game on 1440p"? what else?

3. I see that Dell 2415 appears to be on sale for approx 140 on Dell OUTLET. Is that where my next jump should be? I believe the 2415 was really recommended throughout DS.

4. It seems that monitors rarely dies so making a justification to buy a new one is really tough as both my monitors are working fine and I am not really complaining at all on graphics, more like i don't even know if i will notice any difference getting a new monitor. So I want to ensure that if i do get a new one i want to "notice a difference" and so not sure going up an inch would help.

4a. So would going to 27 inch be the "de facto" solution? and if so,
https://www.monitornerds.com/best-gaming-monitor-for-you-144hz-1440p-gsync-freesync-4k/

am i hopelessly pigeon-holed in spending $800 for "these types" of monitors? if so i guess I will have to wait. I saw the other thread about 1440p and those monitors are 600+$


4b. if "size" is where i shouuld make the advancement i see some 27inch below 200$, but it says 1080. So just wondering what is the right move..
http://www.newegg.com/Product/Product.aspx?Item=N82E16824014378



5. Does Gsync even matter? not reallly sure what it is..


so all in all, just making sure I am really making a difference because this is absolutely the last monitor i'll be buying for a loooong while and I may be pushing myself to make a call, esp with the refurb dell U2415.....
.
thanks guys...

Thanks DST4ME, seems like the game here is to wait a little bit....

But would you say it would be a waste to get a 24inch with 1440/ips/144hz/4k?

and lastly...the 1070 can support it right? or do I have to dial down on my game settings or it depends on the game? because if i go up in monitor size/resolution and i have to lower my settings on my "new 1070" then it just sucks ....lol