It's close, but doesn't quite have the same semantics: with your syntax, the variable has to be at the end, but using the @ for splicing, one can write (+ 1 2 @lst 3 4).
Yes, which also means the @ cannot reuse the lst object in this case, and therefore shouldn't do so when it happens to be at the end either. The dot is a notation for CONS, while @ would require copying the list that is spliced in.
Both . and @ are very useful and would be great to have available in any context.
