Very easy answer : They have to keep the rest system, and... as in tabletop d&d (and former BG versions)... Larian can/should add potential random encounters during the rest
Not as easy as all that. Firstly it means designing a large number of interesting random encounters for the rest, just throwing random monsters in the way the OG BG games did is a bit dull.
More importantly though it actually exacerbates the biggest problem resting has which is the 5 minute day. Every time you rest you will want to make sure you have resources available to deal with a random encounter. This means wizards can't just cast their best spells with impunity they have to leave at least something back but it also means groups are even more strongly incentivised to rest after every fight, if they wait till they are low on resources they may not be able to get past those random encounters.
The solution is to limit resting somehow. This takes a fair bit of finesse to make sure it doesn't feel silly and the player isn't locked into no win situations or disincentivised completing side quests. But I can't think of any other way around it.
