Morgan hasn't shown he can run anything other than the 9 route effectively.
Henderson & Meachem weren't great route runners & often got taken out of plays when corners were really physical with them. Still in all, they made a pretty good living running primarily deep routes only.
Nobody truly knows if Morgan had improved running other routes due to his injury but the potential is there. Unlike both Henderson & Meachem, Morgan actually has quickness in his ability to move laterally. The other two were only straight line speedsters.
Morgan had also flashed the ability to catch passes away from his body with his hands only which was something Meachem & Henderson had problems with. Morgan has also showed he can go up & catch passes at its highest point. That's something those two former receivers lacked the ability to do as well.
The book is still out on Morgan as to his overall development as a receiver. This is why losing him for season was so disappointing along with losing someone who had the potential to have a breakout season at the receiver position.