The VAT is only occasionaly deducted at the source. Most of the time you pay it and claim it back within 6 month after closing. The main problem with leasebacks is the same protections you mention hamper capital appreciation.
By this I mean if it costs 100k with a 5% yield over 11years. Even allowing for rent increases, which are normaly 2 thirds of INSEE index every 3 years, it is not attractive to buyers if you want to sell it on - This is because if you price at at 130k they buy still gets the rental agreement you signed up for so 5% of 100k becomes less than 3% of 130k so it not attractive at that price. So you either sell it for a small profit or wait until the end of the lease. The majority of leaseback, by the way, are renewable at the descretion of the management company, so you may have no choice but to renew.
Like section 23 properties here they tend to be in areas that developers would not otherwise build in. When they are in better areas they tend to be refurbishments.
I have not heard anything about a change in legislation about the VAT??and I know people involved with them who have not mentioned it. What is your source on this ?? as I suspect if it was true it would be heavily pebbled