Really, the only real reason to play on anything above 1.7 is most servers may not support it any more. I don't know for sure, but 1.7 was released in 2013 or 2014 (Which is it? the newest version when I got Minecraft was 1.7.10), meaning that I'm assuming that the oldest supported version for most servers will be 1.8 or 1.9, and 1.13 will be released sometime in the next few months, so yeah.
Well, also, Minecraft maps will need to be in at least whatever version it was released in, like Asleep needs to be in 1.8, it's sequel needs to be in 1.10, etc. Some builds, like houses and cities and such, may be able to get away with going 2 or 3 versions earlier than it was built in.
I understand it is a very old and outdated version now, but as I'm only interested in SP it shouldn't be an issue.
Versions 1.7 and 1.8 initially were major shifts upwards in performance demands, paired with some issues, as you noticed. I believe the issues may have been mostly worked out, between new versions of the game, Java, OptiFine, etc. perhaps. My hardware has not changed in years, save for a graphics card upgrade on my desktop.
My desktop plays 1.10.2 very well for me. I use OptiFine. I play with the maximum render distance of 32, and a lot of anti-aliasing thrown on top for good measure (this really hurts performance) and still maintain nearly 60 FPS (1920 x 1200 resolution), which is my refresh rate, unless I am very near/looking towards a lot of mobs (like my village which has a lot of villagers), then maybe it drops towards the 40s. I'm using a pretty old now platform with this computer consisting of a Core i5 2500K and 16 GB of RAM, although it has a more recent GeForce GTX 1060 6 GB and an SSD.
I think as these performance issues affect some and not others my best bet is to do some testing first, trying every version from 1.6.4 up to the latest release to see how much the performance is impacted, and whether or not the new additions are worth the drop in performance.
My system is also running on an old platform, Ivy Bridge 3770k, but everything is heavily overclocked, and I do mean heavily, which puts me off updating as only the newer Intel SKUs that easily push 5GHz or higher are really worth my attention, but at €700-800 just for a platform change and maybe 20% more CPU horsepower, I can't justify it yet.
Didn't versions 1.3.x to 1.6.4 have an issue to where the Far render distance, which should have been 16 chunks, was only rendering something like 10 chunks? I recall this being because 1.3 changed (or rather got rid of the old) single-player in favor of multiplayer (which is also when the LAN feature was added as a result), and the internal server was set to 10 chunks regardless or rendering distance.
A bit unrelated, but the early 1.7 versions also had a similar issue if I am remembering right (they had some issue with render distance beyond a point not working, I know that much, and something made it more apparent here which made many people comment on it) until it was finally fixed.
I can't speak for versions below 1.7, but yes, you are correct about the render distance bug on 1.7, I totally forgot about that. Damn, that might also be a killer for me. If I remember correctly I read that the render distance physically wouldn't go above 8 no matter what setting was used, which for me is far too short.
I really hope that isn't an issue on 1.6.4 or at least hopefully there's a mod or fix for it.
Don't get me wrong, 1.2.5 to 1.6.4 were nostalgic times for me, but vanilla to vanilla, there's actually a very different (and positive) change to the game comparing those versions to the latest ones, so I can not agree with this assumption. I can see why you might come to that conclusion looking at a list, but I'd recommend you to try and see despite the list, because they genuinely feel like very different eras in the game.
The new combat, the new terrain and biomes, the completely overhauled End dimension, the elytra, the new blocks and terracotta, new water temples and woodland mansions, as well as appropriate mobs, also other new mobs, major changes to storage potential with shulker boxes, and I'm just scratching the surface and I'm sure I'm missing a couple of other notable ones. 1.7's terrain generation did take a few steps backwards (mostly because of an overly aggressive climate system that was introduced) as well as forwards, and there were the initial performance issues with it and 1.8, but that aside, everything else is great with the newer versions, and now you have 1.13 coming overhauling the aquatic aspects of the game
Yeah, I get what you're saying; looking at a text list is one thing, but seeing it in-game is a totally different experience. You are most probably right, but I spent some time last night reading about TheMasterCaver overhaul mod that effectively adds all (most) of the new additions that were added in 1.7 and above, plus a lot more. It's mods like that which make me feel 1.6.4 is still very appealing as most things can be quickly modded into the game so you're not missing out too much.
Again, I think I need to do some testing to see what I would potentially be missing out on versus the performance hit. My rig is still on the high(ish)-end although an old platform, but the shaders I like to use, plus running at a fair high resolution (3440x1440) they absolutely kick the poop out of any system regardless of how new or powerful it is, so I need to run on a version that offers good vanilla (base) performance otherwise I struggle maintaining a reasonably high framerate once I've installed the visual mods.