1) sorry but IB lag on eSignal of about from 5 until 11 trades in fast market with stocks that come for Nasdaq 100. Sometime it happen that eSignal lag (about 15% of time). Also, in every case, IB skip many prices that you can spot easily on the T&S.
2) how eSignal integration could help you, it depend of your trading style, but for intraday traders, this is more critical to obtain reliable information and make the transaction quickly, if you have two applications for do it, you waste important seconds to switch between them. If your timeframe don't required it, this will not too critical to obtain it. Also it seem with the next release, for fan of TS style, that it will be possible to buy and sold by programmation inside eSignal.