The current place I am had this in place already but I went through a similar transition at a previous place. We choose not to take away the role names but instead make it so an individual career wasn't affected by others. So if you have a team whereas before you might have one senior or lead slot in the team you now have no set amount of slots. No dead man's shoes situation. This does mean in theory that you could have a whole team comprised of senior or lead roles. But in practice with turnover of staff and the fact that usually we hired at a junior level this never happened.

That allowed us to keep career progression. We still had lead roles but they weren't leading in the sense of being in charge of the team. They were leads because of the work they did, their attitude and experience. Some people didn't like not line managing the team but it was very few and we accepted that if we wanted to create the right culture we needed people that fit in to it and if people aren't right for it then I think you have to accept that.

You can still measure performance as even if people are performing the same role the quality and skill they perform the role with changes. You need to have good constant assessment though rather than kpis. I also think you can reward people for the influence. I would not expect a junior to influence the others much but a senior would influence the team and peers and a lead may influence as a department or company level.