You could always have like a piece of paper handy and add ticks next to characters names as you get the approval messages. One tick for "slightly" and two for just "approves" to get a general sense of where you stand with one character in comparison with others.
I usually keep an spreadsheet handy when I play Neverwinter Nights 2 (as it doesn't have a bar either), it's helpful for a quick check. I'll probably end up doing that with this game. It's probably a 100 point scale like it was in the last two games with minor and major being anywhere between +1 to +5, or +10 to +25. With my recent shoulder impingement and minor onset of carpal tunnel, I don't have the ability to sit and play for 25 hours straight the way I used to and with 9 characters ongoing that's a lot of data to keep track of on top of everything else. The bars were a nice spot check for progress without having to dig out the journal or run around and talk to everyone, exhaust all the dialogue options, or end up 80 hours in with someone stabbing me in the back.
While having Isabella in my party isn't a chore, I do have to build my party around her for the first two acts of Dragon Age II to make sure I get the required influence to keep her from running off (not that I blame her). That would be a nightmare without a bar. There are critical moments like that in both games where you need to be at point X with a companion in order for B to occur. This can even be after you've done their personal quests and in a game like Origins that's a hundred hours long it can be hard to keep track of it, especially if the indicators are subtle. Like Zevran, are we the kind of friends who are friendly friends? Or is it, yes but not friendly enough for you not to try to kill me when your old bosses come knocking? Sometimes, even with his dialogue options he's not at the point to say: I would die for you if necessary but let's send Alistair in first, yes?
The problem with the system is that it relies on the characters and the surrounding narrative be able to communicate it when it happens clearly enough for the audience to pick up on it. It's like the rivalry system, most players assumed rivalry was negative or punishment instead of just disagreement because that's how it was in Origins. The rivalry has since been nixed, but players who got used to the system still wonder if it's happening or not happening. It's really unnecessary to hide the math and really just irritating overall.