I totally agree with you. Barcelona and Manchester United have a rich history of playing each other on the European stage and it's interesting to see how their recent form stacks up. The change in coaches and players has definitely brought a new dynamic to this match up and it will be interesting to see how Xavi and Ten Hak's tactics play out against each other.
And you're right, the head-to-head record shouldn't be the only deciding factor in this game. Both teams have been playing well lately and it will come down to who shows up on the day and executes their game plan better. A draw at Camp Nou would definitely give Manchester United a boost heading into the second leg at Old Trafford.
If you pay attention at the beginning of the season, these two teams did disappoint, but slowly they have shown their best quality. So far Barcelona has secured one trophy this season, while Manchester United are also getting closer to the EFL champions, there is not much difference in quality between Manchester United and Barcelona at the moment. So it is still quite difficult to make predictions, especially the matches that will take place home - away.
Two weeks into the match and both coaches should have found a strategy pattern in playing and also analyzed the deficiencies that they have to fix, in Manchester United's defense there are still problems while Barcelona is also experiencing the same thing and lastly in my opinion the strategy will affect the outcome of the match.