A purely terminator army does not work so well. You'll either win big or not at all, in other words your list is totally unbalanced.
Firstly librarians have lots of positives like their hoods. However they have Ld9 so they do not live up to the expectations.
You'll want a banner and an apothecary as these are a good deal.
You should have some
LCs in each squad as you need the extra attacks.
OK now the number of squads. I would go for 4 squads maybe 5. They are great but they can not deal with all challenges.
So you should take units to support units to cover the gaps in termy capabilities as it were. Termies are pretty immobile only have missiles, will struggle to get into
cc and have no melta coverage.
Dreads, typhoons and preds I feel work well. 2 of them are mobile, have a range of shooting that complements the
CML and will take ap2 guns away from the Deathwing and typhoons are just cheap.
Others like bike squads for homers, scouts for the
BS and vindicators. For me they do not fight with the deathwing on the battlefield they fight elsewhere.
Hope that makes some sense

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