I actually really like The Silmarillion, but yeah, it's a pretty dry read, even compared to LOTR.
If by some miracle a series of Silmarillion movies (either theatrical or television) happened, I'd split it up something like this:
Movie 1: The forging of the Silmarils and Fëanor's quest to retrieve them after their theft by Morgoth (Ainulindalë and the pre-Silmaril history of Arda summed up during opening credits)
Movie 2: Dagor Bragollach, death of Fingolfin, Beren and Luthien and their quest for the Silmaril
Movie 3: Nirnaeth Arnoediad, capture of Húrin and the tragedy of Túrin Turambar
Movie 4: Tuor and the fall of Gondolin
Movie 5: Eärendil's journey to Aman, the War of Wrath, and the end of the First Age (final scene being the Edain sailing for Númenor)