Yep, mind charge + the Megido spells are your defacto golden hand killers. And guess what? Naoto gets BOTH.
For the most part, the only dungeon you'll ever truly feel a desire to grind in is Yukiko's. Like most games(in terms of SMT(yes I know Persona isn't one technically)), the difficulty is very front loaded. You have very few social links, the ones you do have are low, money is tight so you can't go too crazy with the compendium, you lack the ability to restore you SP inside the TV just yet, etc. If you always clear out the old dungeon again to get to the new optional boss fight(and you always should since there's always a character specific uber weapon in the room with it), and then clear out the regular dungeon, you'll be overleveled almost always. This gets worse if you have a knack at killing gold hands. In
dungeon I'm lv80 now and the shadows are lv66.
For anyone confused about how the Persona system works, just make sure that your persona isn't too low in level in comparison to the MC, since unlike your party members, the stats of your currently equipped persona are your actual stats. If you have low END for example, you will find yourself getting hit much harder. The key to using the most of what the game has to offer is to realize that you can gain upwards of 6 levels the second you fuse a new persona if your social link is maxed with that Arcana. You can't make a persona that's higher level than you(level 55 MC can't make a lv56 Persona), but if the end result is higher, it's all good(level 55 MC can make a lv55 Persona that levels up to 60 the second it's made thanks to social links). This is good to get some abilities earlier than normal.
Just keep that in mind and keep a well rounded group of personas with you, and you won't have much trouble.