Personally, Gaiden is a totally different game compared to FE1 or any other title in the series because with things like dungeons, Weapons and items that improves your stats if they are equipped, explorable town and magic being no more some kind of weapon, but something that the characters learns by leveling up and that costs HP(which is considerable as MP in this game), the game feels more like a traditional RPG than a real strategy game.
In a certain way, you could say that Gaiden is to FE what Zelda 2 is to the TLOZ series
Anyway, since you are having fun with FE1, you should give Gaiden a chance because, while they are both very different as games, they still suffers of the same problems(the unique mechanics of Gaiden are something that you need to try yourself since you may or may not like them)
I hope I answered your question well!