Full football gear changes speed radically ("Football speed") because generally of added resistance to flexibility! The arm movement is far more restricted in pads then without. I would also imagine the pants, inserts and pads would add more resistance than sprinters spandex, but something tells me Nike is trying to close the gap. Now how does this translate to football speed vs. track speed. Lets say guy A is slower than guy B in the 40 m on the track but guy A is faster than guy B on the football field. How can we explain this? Guy B may have a greater Range of Movement through his shoulders, arms, and legs which compared to guy B may explain why he was slower in pads (yes arm/shoulder/core movement is crucial to speed, don't believe me? Try both ends of the spectrum, arms straight and shoulders perpendicular to track vs. full range of movement). Or we could say that both guy A and guy B are identical in size, weight, range of movement in sprint, etc. but vary psychologically. Guy A has a tough-man psyche, he embraces the extra resistance while guy B sees the pads as hindering his speed, complaining about it to himself, until the imagined difference becomes a real difference and completely believes he can not run as fast in pads and thus runs slower. Also another way to look at it is the difference in shoes, beyond the obvious difference in weight, sprinters spikes tend to force a person to run on their toes and the spikes are far more flexible thus less resistance(you can fold them in half without much effort). A football cleat has a much more rigid structure and has to be for obvious reasons and thus can not match the weight nor the flexibility of a track spike. The same biomechanics are in play with the foot just as with the legs, shoulders, and arms. In fact there are even more variables at play, and I really could go on for days about it but yes football speed is a reality, deal with it!
Now for who is faster on the field, T-magic or D-Rob? Most likely no one will ever know because the difference is so minute. T-magic has an unbelievable burst and great top end and likewise with D-rob but it seems like it takes D-rob a few more steps to get up to top speed. When evaluating speed look at the time it takes between 10's or 5's, don't look at the leg speed! D-rob may appear to be running faster when looking at the legs but that is only due to his shorter stature (must cycle his step faster and no there is no way D-rob is 6' definitely closer to 5'10" than 6') In the end this discussion is pointless and silly but yet entertaining.