I would say Gent-Wevelgem is among the top 5 races just because of the tactics and exciting racing.
It isn't close to anything else with the echelons and the location of the hill zone in the race. The last 30K are flat but those make, especially with some wind, for some of the most exciting and unpredictable racing that we have seen the last 10 years.
I would say it's often a better race (tactically) than Flanders, and while Strade is aesthetically beautfiful, it's getting more and more predictable as well. Both Strade and Flanders are just a bit too hard so they predictably filter out the weaker riders, and only the strongest few (less than 5) fight for the win. While many spectators like that, I find it often too predictable and thus boring. After a Flanders race, the conclusion is too often that the strongest rider won, after he duly attacked on one of the last 2 hills, while at Ghent-Wevelgem, because of the fast run to the finish, many more things can happen than the best guy winning. There is just much more food for thought. Maybe not necessarily this year, but just look at the edition Paolini won, or the one with Sagan and Terpstra freewheeling letting GvA go, or last year with Mads Pedersen winning while WvA and MvdP cancelled eachother. Even this year, with a logical outcome (WvA winning), nothing was too sure until the finish, and the way Bennett got dropped is one of those moments you won't forget. And if they had broadcast the whole thing, I am sure I would have sat out the whole 6 hours watching the race.