If it was me and I knew in advance that Angle was going to be ending his career at the "Showcase of Immortals" I would have had him make the announcement the night after Royal Rumble and then make the announcement for the match at either Elimination Chamber or Fast Lane instead of the way they did it. In my opinion the build for the match seems either like a last minute decision or just like something they weren't sure about, but then decided to pull the trigger.
I know that someone out there probably thinking that the only likely explanation is that they will replace Corbin with someone else this way they won't have to build up the match and that is possible. My only issue that is why bother doing that and not go the route of just letting the announcement pop the ratings and get fans excited for the one last meet up between two legends. I of course am talking about the John Cena choice for him to face Angle at the big event on April 7 as that is one of the few names I think would be a good choice as you would have no need to build the match as it would hype itself.
Overall I think this is one of the issues with this years Wrestlemania as the company is relying on a lot of unproven commodities to try and sell the show and not spending enough time building. I do believe that things will change following the show when those who have joined the creative team recently get the chance to build a new arch, but this was bad time for that to happen. In simple terms I am saying that my interest in the big event is at a low not because of the length, but due to the fact that it just doesn't seem the like company is giving the effort they normally do at this time to keep your interest.