I voted yes.
A hybrid system would be great for btc and probably secure the network in a less centralized fashion as many many more nodes contributed to PoS mining.
I doubt that the bitcoin community / foundation / core devs would ever have the balls to make it happen though.
They don't need to make anything happen. I already mentioned one example that requires no soft/hard fork at all and simply requires a wallet that many would happily adopt.
Sidechain or not. No need for burning bitcoins, as someone could simply create a TaPoS blockchain that mirrored and synced the distribution of BTC and than have a wallet acknowledge both blockchains but have the TaPoS layer hidden where only BTC is used and the TaPoS layer acts to add another form of security that could have 1-30 second confirmation times in addition to PoW 10 min confirmation times.
I.E... pay for a cup of Coffee the confirmations start rolling in this way:
TaPoS 1 second confirmation, TaPoS 3 second confirmation, TaPoS 5 second confirmation, TaPoS 10 second confirmation, TaPoS 30 second confirmation, TaPoS 1 min confirmation, TaPoS 3min confirmation, TaPoS 5 min confirmation,TaPoS 7min confirmation, PoW Bitcoin 1st confirmation ~10min, TaPoS 13min confirmation, ect...
This would allow you to have instant confirmations and better security because now you are trusting full nodes and miners and you could detect a PoW 51% attack if the TaPoS confirmations weren't confirming while the PoW confirmations were.
You wouldn't even need a softfork or hardfork to accomplish this, just a TapoS blockchain and a wallet that acknowledged it.