hey, yeah Im a huge UR fan, playing it in all formats like Legacy, Modern, even Phoenix in Pioneer so UR for Highlander felt naturally for me playing. Its true that RUG has better threats overall while UR is much stronger in mana denial and free wins through Moon, B2B and PoP. RUG makes a bunch of MUs like 4c midrange/aggro more consistent with its better threats but its more likely to loose against something like go wide strategies like
Scapeshift ore big ramp stuff. UR shuts those shells down way better in deploying threats earlier and playing a Moon. In a vacuum Id say W6 + Oko are still a little better than PoP + Moon but its quite marginal imho. To the cards you mentioned:
1.
Dismember -> I played it the entire time until I replaced it with
Mine Collapse like 3 months ago.
Mine Collapse doesnt cost life and also targets planeswalker, this had been huge!
2. Urzas Bauble -> the story here is the same argument for not playing
Peek, you do not manipulate your draw (!) which makes it only a replace itself card. Mishras Bauble does cantrip when you combine it with a fetchland or T
Scour /M Note effect, thats the difference. I could see including Urzas Bauble now with the new Iconoclast also but I dont have the space atm.
3.
Bomat Courier -> doesnt have much impact if its not in the starting hand. I try to be as close to Legacy/Modern as possible with those list and
Bomat Courier is most of the time a bad topdeck unless you cast it turn 1 otp. The effect is also not that great when you redraw
Gush, DTT, ExIt so its kinda optimal to find them under
Bomat Courier, otherwise you mess up optimal draws.
4.
Memory Lapse -> in UR you need to really deal with the cards youre facing permanently unlike Grixis or Jeskai which have actual ways of dealing with x/4 or planeswalker once resolved. So unless you go
Memory Lapse into Moon/B2B the card isnt where I wanna be in the deck. The tempo is rather marginal.
Key in Highlander is to
thrive consistency so I try to minimize "atm" cards and rather go for all time stars being good in multiple situations. Thats why I did cut
Flusterstorm and
Gut Shot also, they had huge impact in specific matchups but werent good over a long period of time in various matchups. I replaced them with an other threat and
Mana Leak.