In a vacuum I would rather have Herbert than the unknown. In the real world he is due 30 million dollars this season, and the contract continues to get more expensive. Herbert has always had great weapons around him, but last season when those weapons started to dwindle due to injury or ineffectiveness, things predictably fell apart. After the Detroit shootout things got pretty rough.
We all know this offense as constructed is pretty bad. The loss of the #3 pick with no other first rounders AND the huge chunk of cap taken up by Herbert will make it extremely difficult to build around him.
Like most, I want a generational quarterback, but I don't believe this team is ready to support that, and virtually anyone that comes in here right now to be under center is being set up to fail. Looking at the first round QBs who have become good or elite the last 5 years or so (Mahommes, Burrow, Herbert, Tua, Allen), every one of them was inserted into an offense that was already built to succeed, or added elite players in a very short time.