I'll do 16 onwards as that's when I started watching:
16 - Definitely should have been Rock/HHH.
18 - I appreciate WWE still followed their own rules by having the RR winner in the main event, but Hogan/Rock probably should have gone on last.
19 - No change, Rcck/Austin were both going soon and HHH/Booker wasn't main event worthy. With a lot of marketing for the show surrounding Vince/Hogan I guess that was a possibility but I'm glad it didn't. Besides, WWE were still serious about Brock at the time, so him having the big show ending
moment was more important long term (well, at the time).
20 - No change
21 - Obviously HHH/Batista worked out for the best as Cena/JBL sucked, but with Cena moving to Raw soon and becoming the face of the company, surely his big title win should have gone on last? Debatable.
22 - Right decision. Rey may have won the rumble, but the Smackdown main was very thrown together. Cena/HHH had the big match feel.
23 - The most debatable IMO. Taker won the rumble so his match with Batista had every claim to going on last, especially after they tore the house down. But Cena/HBK did have the better build, even if it wasn't the original plan.
24 - Edge/Taker didn't scream main event to me, but what other options were there? Floyd/Show had potential to suck (it didn't of course), the triple threat could have if Orton didn't win (and with HHH winning the belt a month later, why not do it here?). HBK/Flair maybe, but again match quality was up in the air beforehand.
25 - Hands down should have been HBK/Taker. It's the 25th anniversary, you've got the WM streak and the guy nicknamed "Mr. Wrestlemania", and it's in both men's home state. It's a marketing no brainer IMO.
26 - Fine with what we got, but wouldn't have minded Cena/Batista going on last.
27 - Ouch, I guess Cena/Miz was the right call of the matches on the show, but it probably was the wrong match to begin with.
28 - No debate here.