This is the only way - gotta save those 3 spell slots!
My table's homebrew rules give single-classed Warlocks extra spell slots equal to their proficiency bonus (and those extra slots only come back on a Long, rather than a Short, rest). Warlocks no longer have to keep begging the rest of the party for multiple naps during the adventuring day, which helps keep the session moving, and it allows the Warlocks to do something other than Eldritch Blast before they get to the obviously-signposted-final-boss-fight.
It's just totally fucking stupid that a Warlock gets less magic than an Eldritch Knight or an Arcane Trickster for the effective adventuring day. The theoretical 3-5 encounter adventuring day is also fucking stupid unless you're playing a DragonBall Z mod, where it's ok when getting through a single eight-hour period takes two months worth of episodes.
The d10 giveth and the d10 taketh away
