Yellow card for faking injuries

Make it red, and add a multi-match ban for repeat offenders. This is a culture problem in the sport that should have been dealt with years ago. I can only imagine how effective it would be to just send off a player for simulating. No questions asked. I would love to see the look on their face when they flop down and are immediately escorted off the pitch.

Soccer: yellow card for faking injuries

Yellow card for simulation is already a rule. It's just not applied all that consistently, possibly because it's very hard to be sure that someone definitely wasn't fouled and also was deliberately feigning anything, as opposed to genuinely being hurt or at least being knocked over by a nonetheless fair challenge.

Microphoned ref is becoming a thing now, but I absolutely hate it. Just like VAR it slows the game down horrendously and is not needed. Refs have the tools they need to run the game (including hand gestures and red cards, as you said). They don't need to explain every last thing verbally.

Is a yellow for simulation just a Premier League & UEFA thing then? I assumed most top flight leagues did this now

Miked up refs should have been a thing for years, it very obviously will reduce corruption. In rugby, anytime the ref is making a decision it's all over the PA, plus you can get a little earpiece in the stadium to hear every single word they say

I think a simple matter that if you roll around on the ground "in pain," you get removed for medical attention and for the rest of the game for monitoring. If you're injured, you're injuried. If you're being a whiny baby, you don't deserve to be in the game. If you're faking, you deserve to be ejected. But in all cases it comes to the same conclusion.

Oh, and this doesn't automatically mean a foul. It's not like a person can't get hurt when no foul occurs. I hurt myself stepping out of bed in the morning.

yellow card for faking injuries…and for protesting with the referee.

Huge yes. I support the others saying it could even be a red card. The astonishingly bad sportsmanship from soccer players compared to other sports is a big reason it will never be taken seriously in countries like Australia. Diving is nothing short of cheating, and it's developed to such an extent that even children are frequently imitating the stars they see on TV and doing it in local club games.

In Australian football, which is played on cricket ovals ranging in size, but ~150 m long is a good ballpark figure, it takes very little talkback to the umpires (tbh, I've seen the rule overused in cases where it really didn't seem appropriate) before they'll march you 50 m. The opposing team gets not just a free kick, but a free kick from 50 metres closer to their offensive goal than where the original infringement took place.

Football: proper helmets

Assuming you mean gridiron football, I don't know exactly what you mean (how are the current helmets not "proper"?), but I would say exactly the opposite. The illusion of safety the helmet gives is part of what leads to concussions and CTE.

I'd do away with the helmet entirely. Go bald, or with a simple scrum cap, like in rugby union and rugby league. Techniques will have to adapt somewhat, but that's how all sports have to adapt to technological changes.