You're failing to understand that your defensive record is not purely down to Eric Dier. I've given you an apt comparison to highlight where your logic falls on it's face, you naturally decline to acknowledge it because you either are not smart enough to understand it or you know you're wrong but you're arguing for the sake of it. Both of our starting midfield players are better than Eric Dier. Carrick is better in his passing role that we mostly rely on from him than Eric Dier. I'll give you a comparison of stats that suggests that Marouane 'Elbows' Fellaini is more useful player than Eric Dier. So even him as a squad player, a role he wouldn't be content with, is quite frankly questionable.
There's only as much I can do, if you're failing to understand the very basic concept that's been highlighted by me 2-3 times when talking to you, there's literally nothing I can do. Yes, our CDM needs to be upgraded but not with Eric Dier, because quite simply he's not good enough. We need real quality to upgrade it so that Herrera becomes the squad player who fights for the place. Not with another player who's not good enough to displace Herrera.
On the flipside, sure, you're higher than us in the table but you're also out of Europa, a competition both teams were in. You haven't won COC, you might still win FA cup but you may as well finish this season with 0 trophies, top 4 being the very paramount of your achievements for the second season running and that's about it. I'd be very cautious with branding your team 'much better than United' because, as far as I'm aware, there are no cups for 2nd, 3rd or even 4th place in this league. Be funny shall we win Europa (which is still possible) and you'll end up with sweet feck all.