If I could mail you my copy of 6 to play on a SNES without having to worry about it being damaged in the mail, I would. 6 is actually really good. It's on tons of top game lists on all sorts of sites, and you'd be missing out if you didn't play it.
Purchase it on the Wii virtual console (it's marketed on there as Final Fantasy III). Or if you have something that uses iOS, it can be purchased on the App Store.
Well...alright, here's the thing, I have played through some of it. I'd seen it on so many lists that I started it a number of times, even going so far as to buy it on PS1 a 4, 5 years ago. Ironically, though, no matter how many times I start it, I can't get into it. I've started it on the GBA, PS1, and even the VC (if I recall), but ironically the only FF I've gotten less far in than it is Final Fantasy II (and III, if I recall). I'd imagine it's genre fatigue, as in terms of gameplay, at the beginning, FFVI is pretty standard TBRPG. I may be able to get into it one day but...it's a struggle.
Not big on JRPG's in general though. Too much grinding often too linear, and often you can't even role-play.
That's not really much of a thing, anymore. In the...up until, I'd say, the mid-late PS2 days that was prevalent, certainly, but the JRPG is far more diverse and varied now than it's ever been. Even more old-school RPGs are shying away from grinding or change it so that grinding is less of a...well, a grind, and is either actually fun (P4 is a good example of this, as a successor to the grind-heavy P3), is brief and rewarding (The Disgaea franchise has been dabbling in this, as of late, as well as the HDN franchise), or is completely nonexistent (Final Fantasy as of its latest non-MMO entry, Lightning Returns).
I'd say there's never been a more welcoming time to get into Japanese RPGs than right now. And I understand why you'd say that they're too linear, but...I dunno. Japanese RPGs, at least if we're talking about modern ones, are pretty non-linear. The World Ends With You, Lightning Returns, Xenoblade Chronicles, Sengoku Basara, the Souls series/Bloodborne, and for a lesser known title, One-Way Heroics are good examples of this. All of these games- which, mind you, don't pride themselves on their non-linearity (well, possibly save for Xenoblade), are good cases of not only the variety of modern JRPGs, but also how linear they aren't. These games are interesting in that choice is very much prevalent. They don't present you with world-changing choices and, really, the only one to have multiple endings on there is Sengoku Basara, but they still stand to be fantastic models for what the player "can" do. None of these games will punish you for playing a certain way and it's rare that any two people's games will be the same for any of them (except maybe in the case of SB). They provide you with options and allow you to play how you want. In terms of choices in the way of morality, the Souls series is this, and it does it less so in the way of "Paragon/Renegade" and more in the way of action and visible outcome. SB has linear stages but a lot in the way of gameplay customization and so, so many endings and alternate events based on stage order. And, most of all, none of these games require grinding (if they did I'd have a much lower opinion of them).
And these aren't even the best examples. I'm not trying to make a case for them, really, but I hear people say things about JRPGs (a term I don't particularly like) that are really becoming less and less true based on models that aren't really representative of the genre anymore.