> If everyone is on-board, I am not sure what is wrong with this arrangement.
I think that insufficient attention is paid in hiring to building a team of people whose interests compliment each other.
The situation you describe is fantastic. Problems would arise only if you and the senior were compared on speed for what are actually two very different kinds of work.
I believe the "full-stack developer" meme did a lot of harm here. It is hard to discuss different strengths of different people openly, when everyone pretends they understand everything equally, because admitting that you specialize on X and can only do mediocre work in Y makes you seem like a loser compared to people who pretend to be great at everything.
I have seen people happy when the database guy was allowed to design the database, the back-end guy was allowed to write back end, the front-end guy was allowed to write front end, and the CSS guy wrote the CSS. Then management intervened and said no, the highest priority task must be done immediately, by the first person available. Afterwards both the happiness levels and the code quality returned to the mean.
I think that insufficient attention is paid in hiring to building a team of people whose interests compliment each other.
The situation you describe is fantastic. Problems would arise only if you and the senior were compared on speed for what are actually two very different kinds of work.