Sorry, but I think you all didn't get the point of that scene. It wasn't just humorous.
Yes, Loki is a brilliant strategist and gameplanner. He fooled everyone during the first half of the film. But how ironic is it that his master plan got ruined by a dull-witted brute?
Loki's problem was that at that point the Hulk wasn't a factor in his plan at all anymore. He thougt that the "beast had wandered off". His plan was to use Hulk against the heroes on the helicarrier - and then bye bye, Hulk.
No one (except Stark) expected Hulk to return.
That's the major flaw in Loki's plan: He didn't know that Banner is able to control the Hulk. No one knew. Banner probably told Stark when they worked together on the helicarrier (that's why Stark asked Cap if Banner has returned - he was the only one who knew that the Hulk would come).
So, since Loki never expected Hulk to be present at the battle of New York, he had no plan for dealing with him. In a calm state of mind, Loki could have improvised. But he just got humiliated by Hawkeye's explosive arrow and Hulk's tackle. Loki was angry. He wasn't thinking at that point.
Every other hero would have waited for Loki to finish his speech. Hulk didn't. That took him totally by surprise. In his speech, Loki said that all of them are beneath him. So it's an ironic scene that shows Loki failing because of his own arrogance. The mastermind got surprised by a stupid beast. The god got surprised by a mortal "lost creature". That's what makes the scene so great.
(BTW, even a wizard can be defeated easily if he is taken off-guard. There are comics where Thor and Loki have a very long and nasty fight - but there are also comics where Thor rushes into Loki's castle in anger and takes him out easily with one or two blows. Hulk, by the way, once took down Ares with one blow by surprise. Everthing's possible

)