After playing Rune Factory 4 on every possible platform throughtout the decade, i have many things to say about this game, I'll try my best to answer your possible questions about this game while giving my honest thoughts.

Oh boy, i never thought i would fall in love with a game that looks like an unseasoned chicken breast, RF4 may be one of the most unexciting looking game, but dear god its a fricking "VIDEOGAME"
I couldn't ever guess that Rune Factory 4 was the game i always imagined as the ideal "perfect video game", it wasn't yet still to this date its the closest thing to my imagination.
Im not talking about you can be fishing, foraging, farming, fighting, romancing, crafting, forging, cooking (In a lot of various types) petting etc. the most important thing ,even the current developers are skipping, is you want to put dedication on them! Yes, in Rune Factory 4 there are absurd amount of content and none of them feels useless, at some point you always see yourself dealing with one of them yet the game doesn't force you, and it knows how to reward you for those.

There are 50+ progressable skills, all of them is needed for your progression, because of attributions are much needed to survive if you want to end the game.
For the combat, its nothing special, for a 3ds game, its awesome. close combat tools aren't that various but i wouldn't say the same for abilities, they are so cool and enough for build variations. Forging and crafting are the 2 most important skills since this game is %50 dungeon crawling, even in easy mode you never find yourself overleveled/overgeared yet you can easily become undergeared and it will be a true nightmare. Don't forget everyboss can oneshot you if you lose your focus on battles. Generally game isn't balanced because the normal mobs can't even answer your swings yet some bosses makes you feel like an ant.
Characters are lively and well-written but don't forget this game is in generic jrpg format, you won't find unforgetable npcs or scenarios, bachelorettes have few good choices but bachelors are lacking.
And the farming in this game is mindblowing, it has soo many layers that it will give you seizures and headaches if you put too many time in it, but if you don't put any time it punishes you HARSH. you can consider this good or bad.

Lastly, is "Special" version really that special? I don't think so, it added two new extra content called "Newlymed Mode" and "Another Episode" to be honest i never found myself dipping in both of them, i tried them, they are short and wholesome yet pretty useless, also i didn't like the portrait motions on newlymed mode, its a bit disturbing, scares me i guess? It fixed a lot of older 3ds version bugs plus added QOL features, unfortunately some non existent sound bugs appeared in this version.
If you try to view "Special" as hd port of a game that was stuck in old generation consoles instead of a content adder it will no longer be a problem, this is the best version for now.
If you are a JRPG fan, it may be a good experience for you, if you are a farming fan, it may be a good experience for you, have fun!