Maybe it is not so good idea to buff shield to native values, because native values I've found on wiki are... interesting
Unless you are able, willing and have support of other balancers to nerf shield skill and put emphasis on shields themselves when it comes to coverage. You can buff other aspects of shield skill, like HP and shield speed.
Anyway, here are (I think SP and original MP) values for native shields:
http://mountandblade.wikia.com/wiki/ShieldsAs you can notice, some shields have hilarious stats if you compare them to cRPG. Most shields are a lot lighter. In general, all are bigger than in cRPG and some are faster, some slower. Not sure are these exact values they use in native multiplayer today, but I remember that Nordic Shield in pre-upkeep cRPG used to have these stats like on Wiki. I later used Steel Shield and believe it was a lot faster than it says on Wiki, believe it was around 80 speed at that time in cRPG, but might be wrong.
Take into account that in pre-upkeep cRPG there was a lot crush-trough weapons. Also archers were stronger, but not by that large margin as some people tend to think. Over the time, and because of low ping spammers like you
and kinngrimm on EU side, people complained a lot about shielders so they implemented many mechanics to circumvent them. Also they helped them by changing kick animation. But also new mechanics like nudge/bash help to deal with shielders quite a bit and doubt that anyone these days can be easily facehugged and spammed right swing like it was the case before.
Because of all that, and growing ranged threat and a FACT that shield break rather easily (I've been breaking any shields with extreme build in two hits and most axes break even most durable shields rather quickly, also swords break shield very efficiently even they should not) think it would be smart to think about giving shield more protection as least while they last. Forcing people to move in shieldwalls is rather noble idea but just doesn't work on pub servers. Also something that irked me very much in the past, shields saving horses these days isn't the issue. Considering overall low HP and armor values horses have think it would be good they can at least protect themselves against projectiles by using a shield.
If you think I'm lobbying for shielders because I'm this week playing a shielder... well, it could be true but I'll probably respec to 2H and keep it that way. Might go shielder on another char, but lucrative call of ranged is too strong to be ignored