>>713299942 (OP)When I think of Half-Life, I mostly think of wandering through hauntingly empty-feeling areas (countryside, abandoned industrial buildings) and just kind of existing as Freeman, soaking in the sense of presence, punctuated by frequent but not constant combat. The TLOU games are really good at that kind of atmosphere too, so that could work.
From a storytelling perspective, it's hard to imagine him being comfortable completely letting go of traditional filmic cutscenes and strictly railroaded walk-and-talks. HL is good at creating a sense that its story will continue with or without you which means e.g. accepting that the player might be looking in the wrong direction at a crucial time. Could easily result in some kind of awkward compromise that pleases nobody.