I'm going to skip events I don't know much about. I'm concentrating on what brings an audience, global participation (across the board) and infrastructure. (Borrowed @intoronto's template here.
Athletics*: cross-country racing
Artistic Swimming: I think this should be removed just because of the judging. Wow, the same teams win the same medals at every event. Inspiring. But, I get that it's a real sport and people like it. Mixed duet instead of female duet, and mandatory 2 men per team.
Boxing: Gone.
3x3 basketball: Increase to 12 teams per gender, 2 groups of 6, top 4 from each go to quarters.
Canoeing Sprint: Add 500m to mens and womens C1.
Canoeing slalom: Cross seemed like it was going to be fun, but I'm not sure. I'll give it another shot.
Cycling: Add a second event for Mountain biking with no new quotas. In Track, 1km time trial.
Equestrian: Gone.
Golf: Controversial, but GONE. It's not important to the big names, and the infrastructure is non-sustainable. Also, I find golf boring.
MP: Kind of like the idea, now that equestrian is gone. Obstacle course will be good TV, probably.
Rowing: I'm good.
Rugby sevens: No changes
Skateboarding: Watched more of it in Paris than any time in my life, I get it now. But I don't think 11 year olds should be in the Olympics. There should be a minimum age for every discipline.
Soccer: Even number of teams for both genders.
Surfing: Gone. It's just impractical, and I don't like sports that depend so heavily on random mother nature. Also, not great for TV.
Swimming: Eliminate semis for 200 individuals.
Table Tennis: Don't care, personal opinion, GONE.
Taekwondo: Fine.
Tennis: Fine, but extend the calendar so athletes aren't playing 2-3 matches per day. There two weeks, use the two weeks.
Triathlon: Fine.
Volleyball: Fine.
Wrestling: Maybe remove Greco-Roman wrestling
Elective sports from Paris/LA
Baseball/Softball: Continue to have it in countries that can support it. I think it's good, but no need for a country like France to build stadiums they'll never use again.
Breaking: No thanks. But gold for Canada!
Cricket: Yes, it includes otherwise neglected South Asian countries.
Flag Football: Gone. Interested to see it, somewhat.
Lacrosse: Yes.
Squash: Sure. Includes otherwise neglected countries. Too many racket sports, but I'd take this over Table Tennis. Sorry, lived in East Asia for many years, still think it's not an Olympic sport. Come at me bro!
Athletics* = New field team event. Countries have competitors in all 8 field events, add up placements like team figure skating. Only three attempts in each event, or something like that. All in a few hours. DO IT.