i mean, change for the sake of change is not always right... nor is it a guarantee the change is going to be good.
Poor sales has less to do with people being tired of the characters they're reading, and more to do with having to read terrible stories and/or writers making stupid creative decisions with the characters people love, e.g. DiDio, Bendis, Tom King, Ric, Bard, MM x Hawkgirl and so on. Other issues include writers not respecting continuity/history, many concurrent events involving the exact same characters, no real plan by the DC editorial in ensuring their lineup all makes sense and is in continuity annnd so on.
If we end up in 5G with a brand new lineup of heroes but with the same issues, then nothing will have really changed right. In fact, it'd be an even worse state for DC cause it wouldn't be poor stories with characters people love, it'd be with brand new characters people will have no connection to.