Hold Person was a problematic spell always. Heck, that it became my go to fear round spell in all the Baldur's Gate games, and the number of 3E characters I saw get chewed up over it, no, it was a problematic spell. Concentration and a save every round makes it doable, but I still think a 2nd level spell for taking someone out of combat for an average of 2 rounds is pretty good as is.
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Hold Person is a poor spell.
At low level, when you first get it.
When a casting of Hold Person represents using up one of your highest levelled spell slots, it simply is too unreliable to be a great spell. At this time, your spell save DC isn't great, and every NPC has a decent chance of saving.
At mid- to high levels, it's a
great spell.
Now spending a second level spell slot is cheap for you. Not only is it no longer one of your precious high level slots, you have plenty of 2nd level slots. More importantly, your spell save DC is reaching towards DC 17 or even higher, so the absolute majority of NPCs will find it a very difficult save to make indeed.
Essentially, the spell is much more reliable, and even if it still fails to hold a person for long, it's no biggie - since you have so many more low-level slots to use.
In short: any suggestion Hold Person is weak and needs to be improved is premature. You need to look at it from the perspective of a level 11 or level 17 caster to truly appreciate it
And that goes for all low-level save to suck spells. They're not meant for you who just got them. They're meant for the pros that have had access to them for more than half their career...