One way to combat this in 5.5 could be to rule picking a lock to specifically be a Dexterity (Thieve’s Tools) check instead of Dexterity (Sleight of Hand), since Theives’ Tools are no longer explicitly listed among the things the Rogue can take expertise in. Though, as you say, without expertise they can still hit DC 25 from 1st level, albeit at a very low chance. Personally, I’m fine with this. Picking locks is a huge part of the rogues’ shtick, and I feel like D&D would have a lot fewer locked doors if there wasn’t a whole class known primarily for picking locks. When it’s that big a part of their identity, I’m fine with them being very good at it. I basically consider mundanely locked doors and chests in D&D like red doors in Metroid after you get the missiles. They’re functionally no different than blue doors, they just exist to make the player think “wow, I’m sure glad I got the missile upgrade.” If you actually want to keep PCs out of somewhere, you need barred doors, portcullises, magical locks, and/or puzzle locks.