The issue with the tax liability in Wohnriester is correct. However, there is the possibility to pay off the tax liability in a lump sum upon entering retirement, with a 30% discount. Additionally, one must not forget that the tax rate is lower in retirement. Due to the faster repayment through the subsidies, the Riester loan is paid off relatively faster than a normal annuity loan with the same rate, and thus interest payments decrease. That should be offset against the tax liability, shouldn't it? Especially if you have several children, you can repay the loan very quickly because of the child allowances of 300 EUR per child.
If you have to sell the house because of moving, divorce, etc., that is a problem. But if you finance a new home or conclude a new Riester contract, then you do not have to pay back the subsidies, right?
The problem I see is the uncertainty. No one has yet reached the end of their Riester loan. So, no one has experiences with the tax liability etc...