I'm sure we'll see more of Elektra soon, she's bound to have a central episode in the future. Other characters need more screen time too which is probably why we've seen less of Elektra. But she isn't the only one who we've seen less of. We haven't seen much of Harry and Floss either.
Harry has never had a huge role in the show... he's been focussed on in a couple of episodes, but he's generally a background character. I think Floss could be a strong character, but in a quiet way. I do think she'll be developed in time, but they're playing the long game with her.