They might be vague, but at least you had the idea that they are going through the hell together, reporting the progress to each other: that Chris isn't in town, that Claire is looking for Sherry, that Leon found Ada, that there is an escape route through the sewers, that Sherry got infected and needs a vaccine, that they need to find an escape from the lab etc. In the remake Leon and Claire meet each other only once during the game, in the RPD, where they only acknowledge that they are both here (at this point none of them have any plan, don't know that Chris isn't here, don't know about Sherry). After that they both magically appear at the same time in the same place at the end of the game. Leon's "who are you?" towards Sherry at the end of the game sums it all.
Capcom resigned from making two campaigns for each character, I understand that. But why then instead of adapting ClaireA/LeonB they adapted ClaireA/LeonA and cut most of the relationships between characters (Claire/Leon, Leon/Sherry) is still a mistery to me.
