So this actually couldn't be further from the truth in your case specifically and I'm going to show you why. I just pulled your data and know exactly how much SPS you're earning and how many matches you've won in modern this year. You're not very active, but if you were and you were renting/staking enough SPS to do what you're doing right now, you're earning about 0.9 SPS per win. That said for the majority of your matches you're earning less than 0.1 and you aren't very active, but anyway let's look at what this proposal would mean for you specifically with the cards you have right now.
You could comfortably play in bronze and if you're good you could maybe hang out in silver, but you'd hit higher level cards probably.
If you're active (using your daily energy) and winning regularly (at least 50%) with bracket appropriate SPS stake/rent, this is what I'd expect to happen for you personally while playing in modern:
In one season in bronze you'd earn about 2x the SPS in one season that you've earned all year so far in Modern.
If you can hang in Silver and keep up, you'd earn roughly 5-6x the amount of SPS in one season that you've earned all year so far in Modern.
So let me ask you a question in return:
Where did this question come from and what makes you think this would penalize you personally?
You're quite literally the perfect example of someone that this proposal should massively benefit.
I can answer this question. If he choose champ, most low level cards become unavailable and his win rate from 50% to 5%. If he choose bronze, all maxed out cards has a cap and equalize low level cards, the money spent on them wastes and his win rate drop from 50% to 40%. Worst thing is SPS allocation is very top heavy(champ has more than half), if you want more rewards you have to choose champ and spend more to max out deck. You may aruge it is designed to be it. but comparing with current system , this is penalty.