I think the fact that they didn't really talk about the fake pregnancy is the thing that bothered me the most.
But other than that, I think it can be sometimes debated when exactly two characters "fall for each other".
With Fadam it was obvious that they were interested in each other when they were talking on the steps outside the school, at least to me. And they hung out during the food drive and in class and we'll probably get some more of that in In Too Deep.
With Eclare, it was clear to me that they first started liking each other when they skipped class and edited their essays. And they had other scenes after that in other episodes where we got to see their budding friendship. I mean, they already liked each other before they became good friends, but during the time they were hanging out we could see that those feelings were growing.
I mean, with Sav and Holly J, we got the one scene where they bond over student council. They talk about having a dance. Fiona mentioned that they'd been spending a lot of time on student council together, but we never get to see it after that, save a few brief scenes before they're kissing in the next episode. The moment it became clear to me that Sav had a crush on Holly J was the scene when he talks to her in the hallway and Fiona points out that he seems to like her, but we never see that with Holly J. They did make his behavior out to be pretty obvious. But it was news to me that she would even return his feelings. It was only when she kissed him at Above the Dot that I got we were supposed to think that she liked him back.
Not everyone are friends with each other before they date. Sometimes someone sparks your interest and you go out with them to get to know them. That's fine. The problem is, we never see Sav and Holly J actually developing as a couple by dealing with conflicts or getting to know each other outside of student council. We get brief scenes with them "having fun".
I definitely think that the reason Sav and Holly J don't get screen time is a combination of the writers not liking them as much as other couples, and also the fact that they seem to not know that the hell to do with them.