In need of some Amplifier advice. Is therereally any point in it with my current setup?

This largely depends on your end goal. Do you eventually want a full-blown system of separates...even considering monoblock amps? Do you definitely want to try the LFT8s? 

Your current AV receiver can probably manage with the low sensitivity of the LFT8s, but as with other planar speakers, they probably sound best with a high power amp. I like Yamaha products, but I'm not a huge fan of their AVRs. IME, their integrateds are in a whole other league when it comes to sound quality. While your AVR is not inexpensive, it still uses cheap, sheet stock heat sinks, a sure sign that they made sacrifices to the audio quality to make way for all the processing tech.   

The Halo A21 is a good amp. It will certainly power the LFT8s without breaking a sweat, but will probably give your current setup a decent boost in performance. I think you'd be ok using the Yamaha as a preamp. No, it won't likely perform as well as a standalone $2K unit, but I believe the amp section is where most AVRs skimp. By going with a new amp, you might manage to bypass the weakest link in your current chain, while preparing your system for a future speaker upgrade.

As for the LFT8s, I haven't heard them, but I wouldn't be surprised if their performance far exceeds the Polks, even when driven by an AVR. Upgrading the speakers may yield the greatest short-term ROI, as long as you listen at moderate volumes. 

@helomech I kind of assumed the power coming out of the Yamaha was  pretty meh and that as a pre it would probably be....decent. 

I'm thinking the Halo 21 or comparable would probably be the most logical first step, since I would need to acquire one eventually regardless. 

I'm not really going for a full blown system of separates. I have looked into two mono blocks as opposed to a two channel amp. 

But all this being said, Eminent tech does offer a 30 day trial for the LFT8s. But I know once I purchase them I'd have a hard time sending them back ;). 

I may just up my budget (which I can do), and go with both hah! 

Hey Mosk, where are you located?

I'm quite familiar with the Polk series and can say if you stick with that, the Halo A21 would be excellent.  The Yamaha will always have its flavor added to the sound, but adding the amp will still yield some major gains. The LSiM are some solid speakers and a far cry from what Polk is known for.  With that said, at their retail price, there are/were better options IMO.

Is this a home theater, 2 channel, or multi-purpose system?  If you went with the EMT, would you have room to actually get them off the back wall several feet? 

Take it one step at a time.  Get the Classe, Parasound or another higher end amp and use the Yamaha for it's preamp (realizing that's most likely the weak link) and see how you like it with your speakers.  I would then look to a higher end preamp, possibly tube preamp.  (I know very little about 7.1 surround since I'm a 2 channel person).  Once you change preamps, then see how much you like your current Polk tower speakers.  If the rest of your speakers are all Polk in your surround sound, then the LFT8's might not match your other speakers, so make one change at a time and give yourself time to get used to the change you made.

But yes, the Polk's mid range is fairly weak. When playing piano tracks and solo acoustic guitar tracks, it's quite apparent that they are lacking.