According to me important Railway Route which should be electrified within 2-3 years are.
1.Delhi-Ahmedabad
2.Chennai-Mumbai via Guntakal.
3.KSR Bengaluru to CSTM
4.Erode-Karur-Dindigul
5.Salem-Karur-Dindigul...
more...
6.Dharmapuri-Hosur-Bangalore
Other important dense routes in UP and Bihar
Konkan electrification should also be started soon to complete within next 5 years.