Certainly the "classic" European routes will stay (LHR, CDG, FCO, MXP, MAD, BCN, FRA, MUC, ZRH, GVA, BRU, AMS, ATH, DME, OTP, SOF).
Regarding routes that used to be operated by EL AL's low-cost carrier "UP", or that have a lot of low-cost competition, they might be cut (KBP, LCA, SXF, BUD. PRG, VIE).
Then there are routes that were operated only 2-3 times per week, that were relatively new or that were not yet started (VCE, MAN, DUS, DUB, LIS) - I don't think they will be flown again or launched.
EL AL's Sun D'Or brand, that operated to holiday destinations may be kept but with much less destinations. (I think they only had 2-3 planes anyway)
In the long-haul market I can see LY focusing on the business and Jewish community cities in the US (NYC, LAX, MIA, SFO), sizing down frequency in Asia (BKK and HKG) and rely more than ever before on code-share to keep serving former destinations (especially in the long-haul market).
It all depends on what their fleet will look like - if their 6 777s will be cargo only and several of their 738s will go back to lessors, this will severely limit LY to offer a network as big as it was before. Demand will also be reduced, as there will be both less business and leisure trips.
In the past two years EL AL has expanded like never before and intended to continue to do so (SFO, BOS, ORD, NRT, LIS, DUS, DUB, LAS, MCO, MAN) and it appears that for the next two years at least this trend will have to be completely reversed.