I really don't think it would've made it any easier to say "goodbye" if they had spent a few final episodes showing the family back in 1971 at the very end; as a matter of fact, to me it would've made it harder. Besides, what could they have done for, let's say, one week (if they had wrapped up the PT1841 storyline earlier)? Now, when Barnabas, Julia and Eliot returned to 1971, I'd say it would've been better to have seen more of the family for at least a few minutes rather than just Liz, maybe having more of them scurrying about getting ready to head off for Roger's presentation. But beyond that, I really don't know what else would they have done? Nothing more could've softened the blow. Best to have just said farewell rapidly and gotten it over.
Gerard