1.7.10 is the best version of Minecraft because of the huge amount of high quality mods available/
The ability to mod the game is what made Minecraft so popular in the first place. People just loved hacking into the jar file modifying classes and other people loved to use those hacks to play a modified game. I remember having to patch the jar manually then later modloader and even later forge came around.
For every feature 1.7.10 doesn't have there's a mod for it.
There are a lot of changes brought by 1.8 which made modding a hassle so a lot great modders left the scene and only a few returned briefly for 1.10 or 1.11. All the features added in vanilla since 1.7.10 pale in comparison with what the mods can offer.
Instead of embracing the modding community 1.8 in fact killed Bukkit made forge mods more difficult to always play a game of catch up with the faster release cycle of Minecraft and with the aquisition of Microsoft the game is about to move away from java, from forge and are creating their own visual only mods.
There are mods in 1.7.10 to make it like 1.8 and 1.9 or even like 1.10 and 1.11. While not all features are available like dual wield or shields is possible to install a mod for that too. In a sense 1.7.10 already had everything that was gonna come out in the next 5-10 years!