Just my personal opinion, but I think the move is more of an economical one. Why produce the 1098 and 1198 in the same platform? Make one engine, leave the differentiation to the suspension bits and maybe the tuning piece. Increase the profit while still offering a badass product.
Now, take those left over 1098 mills, and shoe horn them into the new Monster Chassis and the upcoming Hyperfighter. Theres an idea. Keeping the SBK's ahead of the pack and the rest of the line-up ahead of all other makes in the same class.