full nodes do full features
Again, full nodes, whether they are full archived, listening or pruned nodes, have the same set of rules. The only difference with full pruned nodes is that they dump their blocks to free space.
Providing less services to the network doesn't make you a non-full node.
if there is a hack, bug. you cant just copy and paste the UTXO set to a new computer and continue. you have to re download the entire blockchain again to ensure things did not change.
And if there's a hack and you run a non-pruned full node, you still need to resync. Keeping the blocks doesn't protect you from such attack. It's just that with a pruned node it'll take longer to sync.
there is a reason why people actually use the buzzword "pruned nodes" because it separates the misunderstandings, there are reasons why people use litewalet, spv wallet and other wallets. again to separate the confusion.
However, they are all part of the network and therefore, nodes. Some just don't follow the consensus rules.
But pruned nodes cant validate new block if they dont have the full history of transactions ?
During validation, you don't look on past blocks. You only need to look on the UTXOs that are in a separate directory. Pruned nodes do keep the so called “chainstate”. If you've started from block 0, then you'll have the proper chain state and thus, can validate the most recent block's content.
For me pruned node are like half way toward spv who was not fully implemented ?
No, no, no. There's no validation in SPV. You have to trust that what servers send you is valid. In pruned node you verify everything yourself.
Last time i tried for exemple to add new address or import a wallet into a pruned node it said it had to re download everything ( maybe its not the case anymore or i mis understood something).
Yeah, this is how it works. It needs to resync to get the new address' balance, but since it doesn't have the blocks, it has to re-download the chain.
pruned nodes that ask to re-download the entire blockchain when you import a key, is because your pruned node doesnt even keep a complete UTXO of all unspent transactions.
This is a lie. Emphasis mine;
They keep the complete database of all UTXOs. This is enough to verify new blocks. What is required for validation is that the tx in the new blocks are spending only the current unspent transaction outputs