i've played hgss 6 times and I have more fun each time i play it. its perplexed at first because they seem like they should be boring games
>generic team rocket villain story
>generic npc battles unchallenging
>weak wild pokemon
but realized that hgss is fun precisely because it seems generic - each time you learn of new strategies, new pokemon, that are 'hidden' and are not easily thought of. the game compels the player to search in unexplored locations, explore unconventional strategies, and experiment with new pokemon that you may not think of.
some examples
>using natural gift with shard berry man in violet to defeat bugsy with bayleef
>realizing you can go to route 45 right after getting surf to get level 25 heracross and level 27 ambipom or level 32 poliwhirl
>the 1/1000 level 50 magikarp/gyarados in lake of rage
>learning voltorb flip to get flamethrower ice beam thunderbolt
>getting abra with flip for synchronize nature instead of getting natu
>figure out how to to get level 40 raikou before morty
>figuring out what moves to sketch with smeargle
>gym leaders and elite four are generally more difficult than npcs so even if reg trainers are easy you still have to optimize for battles such as with battle frontier tutor moves
(never battle wild pokemon for experience)
>dungeons like mt mortar whirl islands to explore

and many other hidden gems you can find. i feel in other games the above is shoved in your face (xy) or there is not much to strategize or find (frlg)