Henry was better than Drogba but Henry isn't the yardstick for being world class. Drogba was as complete an athlete in football as you will find. Fast, powerful, outrageously good in the air, like Alan Shearer good (and I know most don't like Shearer) decent on the ground, if he had a decent chance you trusted he'd take it more times than not, smart runs, played off the shoulder, could drop deep and like Giroud would head the ball over the half way line away from his own goal when defending for his team.