Even if players in 1-4 considered not strong as 5-8, I think they still reserve the chance to represent. The rules of selection is somehow made and announced before the tournament, and we shall not change it according to the results. Of course, SGXQA also reserve the rights to modify selection criteria like organizing additional selection matches, but the key point here is that we shall never try to wipe out the top 4 just because "many" people think them no good enough.
Even if they are really not that good, who knows they surely play worse in International tournaments? Even if they do play badly in international tournaments, it's only a tournament in this year. Why not look forward to next years? And who knows how much progress they can make after gaining experience from international tournaments, and how much would it benefit Singapore in next years? After all, they are not that "no good". They have their strength before they have chances for top 4.
Therefore my view is, whether you think they are strong enough, they have their strength and opportunity, and you should at least let them have a try.