No Senkos version is much more powerful. In the normal version of the rules an aligned BG gives you the rating as a modifier to the limit of your magical skill use and you have to be quite close to them if not directly on them. with Senkos version your magic rating goes up by the rating of the ley line, meaning that it gives you more dice, allows you to cast higher levels without risking physical drain...etc. plus you can do it from a very high distance. Senkos version of ley lines are more in line with previous editions of SR, but still even more powerfull than they were.
As for feedback, i would tone Down the distance over which you could tap the leyline, 1 km pr. point of force is quite powerful. Also i imagine that if this was possible, the competition between magical Groups, corps, governments and individuals for control of ley lines would be even more vicious than it already is, so holding on to "your" ley line would probably be quite an accomplishment.