I've recently been using the term "archiver" or "blockchain archiver" for what Core calls "full nodes" (especially the unpruned ones), but let's examine the terms again more carefully to see if we can really iron things out.
First of all, the wallet functionality is separated out now in Core clients so their "full nodes" aren't necessarily wallets.
More importantly, there is (except under Segwit) in a sense no meaningful block validation other than mining itself: if your archiver "invalidates" a block (e.g., because blocksize was too big) and then the hashpower majority validates it by putting it into the most-PoW chain and mining several blocks on top of it, who are the real block validators here?
What the archivers do validation-wise is check *transactions* (ensuring that the sigs are valid and the outputs are not already spent). They cannot validate or invalidate *blocks* though, unless we are merely talking about identifying a block with an invalid tx.
In all other cases (which constitute the Bitcoin security expectation, except under Segwit where many miners might mine validationlessly as they wait for "delayed" witness data), their "invalidation" of the block can be overturned by a miner, making their block invalidation meaningless. Likewise their "validation" of a block could be overturned by a miner if the miner wants to follow more restrictive rules (or even technically for any reason or whim the miner wants), making their block validation meaningless as well.
So I think this brings me to an improved understanding, that "full nodes" are validators in the sense that they validate transactions, but not in the sense of validating blocks. Only miners validate blocks. These tx-checking archivers ("full nodes") can meaningfully invalidate a block only in the sense that they can check that a block contains an invalid tx, but notably - especially under Segwit - this doesn't always mean it won't become part of the longest chain and the miners won't doublespend the second-longest "all tx valid" chain into oblivion, a scenario where Bitcoin is broken of course, but the point is your "full valdiating node" cannot save you against a majority of hashpower that has run amok.
In other words, the only case where "full nodes" can be said to serve as block validators, for more than a couple comfirmations, is one where Bitcoin is broken anyway and they've merely alerted you to that a couple blocks earlier. After a couple of confirmations, the "advantage" your all-tx-checking archival wallet has over SPV wallets here is a Pyrric one: you simply learn the coins you just avoided being fooled into thinking you received are actually worthless anyway, even if you had received them properly, as all BTC have gone to zero.
Thus we might as well just call them general tx checkers, because clearly that checking can also tell you whether a block is a candidate to be accepted into the Bitcoin blockchain in terms of tx validity alone (except when Bitcoin is broken due to miner incentives being severely misaligned). Miners are the ones who actually vote on those candidates (and technically they could even vote on non-candidate invalid-tx-containing blocks if they wanted to destroy Bitcoin, backed by the power to doublespend the longest chain of only-valid-tx-containing blocks to death). And while Bitcoin is premised on miners not voting for blocks that contain invalid tx, it is NOT premised on miners only voting from among the blocks that "full nodes" consider valid for any *other* reason besides tx validity (this is the Core / small blocker misunderstanding).
Miners = block validators = nodes = block voters
Core "full nodes" = general tx-checking archivers (or all-tx-validating archivers if you like), with optional wallet attached
Pruned Core "full nodes" = general tx checkers (or general tx validators), with optional wallet attached
SPV wallets* = specific-tx-checking wallets (with enhanced SPV able to check deeper in the chain for the ancestry of those tx? - an idea
@awemany has suggested)
*I think calling them "SPV nodes" kind of plays into Core's hands, in that they want everyone to see something other than miners as also being "nodes," as they view Bitcoin as something other than a mining (=block validating) network, so that they can pretend that their general tx checkers ("full nodes") have a say in governance by having some kind of meaningful vote on which blocks become part of the Bitcoin blockchain.
