I do not see it as mortgaging the future, just getting a player who may or may not be better a year early, with the additional year to develop him. It's far from trading for an older vet.
You are trading away a shot at a top player the next year for a lesser player this year. Sorry, but it makes no sense to me. You are far more likely to land a good-to-great player in the first than the second. That's just a fact. That's not a shot I'm willing to give up for a second round player. There are 102 1st rounders in the HOF. That compared to 32 from the 2nd round and 88 from all other rounds combined (including the very late rounds that existed before and free agents). That's not a fluke. I'd rather take my chances in the 1st.