It's too early to say if it's a weak case because we just don't know the details. There are (AFAIK unconfirmed) reports that there are 34 charges in the indictment. You wouldn't get that just from the Stormy Daniels payoff so, if true, there's more to this indictment. Maybe related to the Trump Organization fraud? We can only speculate.

This will be unsealed when Trump is processed and arraigned. I believe this is set for Tuesday. Note that processing includes the mug shot, fingerprinting and DNA.

My understanding is the payoff was upgraded to a felony because it had to be. If it were a misdemeanour it would be beyond the statute of limitations. So this isn't even a case where the prosecutor has "insurance" with a lesser charge. A felony seems to require actual intent, as in knowing this would impact the election. Whose to say it wasn't done to protect his marriage, for example? Of course, there may be evidence to support this.

But I have trouble believing the Manhattan DA would indict just on this (alleged) offence. There has to be more to this. Hopefully we'll learn a lot more next week.