Yes
Their definition of mega IRAs is highly concerning
If you're talking about loopholes like Peter Thiel I think that's completely understandable and reasonable
But them calling IRAs with 5 million dollars in it Mega IRAs is insane and an extremely dangerous slippery slope
I think it's blatant robbery for them to change the rules of IRAs after the fact.
If they want to change something change it going forwards on future contributions. But you can't change the rules on already accounted for money
I can agree about slippery slopes, but do you know how hard it would be for one person to get $5 million in a traditional or ROTH IRA the way most people do for retirement? If you maxed it out for 30 years and earned 10% interest you'd have about $1-$2 million. The only people with over $5 million in a traditional or ROTH IRA would be either someone that worked for 40-50 years, started saving when they were very young, and earned an excellent interest rate....or someone who found a loophole like Thiel. I can't imagine there are shitloads of people with over $5 million in a typical IRA for retirement. They should raise that number some though to account for that. If you talk about 401Ks, different story.
2 IRAs that may matter more are Inherited IRAs and Non-deductible IRAs. Non-deductibles, even though they are taxed initially, don't pay tax on earnings until they are withdrawn, so they could get large in value. You could have a large inherited IRA if you still fall under the old rules before 2020 where you can take automatic distributions based of your expected lifespan and you are pretty young. Not that common I don't think.
I think you need to find a way not to punish people that somehow found a way to do it the right way and get large sums in there, but I don't think it would frankly be that much money they'd collect. I don't think it's a good idea to change the rules after the fact, I agree. But change them going forward.
EDIT: Looked it up. There are about 28,000 people with IRAs over $5 million. More than I expected, but I wonder how many of those are people who saved it the way the system was intended (by working hard and saving as they go)?