Interesting point. Cripple is a strong word, IMO.
What kind of WAR would you expect someone like Brandon Workman to generate over a full season? For reference, he posted a 0.7 WAR over 41.2 IP this year. I would personally peg him as a 2-2.5 WAR guy.
Now, Lackey last season posted a 3.2 WAR. So you're essentially losing 1 win from last year when you downgrade from Lackey to Workman.
The next question is what kind of a WAR you can expect from Hanigan (or whoever the other C would be). Over the past 3 years, he's averaged a 1.5 WAR (1.8, 2.7, 0.0 over the past 3). He's coming off an injury, but I still think he can put up a WAR of 2.0. I like him.
Carlos Santana, though, has averaged a 3.4 WAR over the past 3 season (3.3, 3.3, 3.6). So you're bumping your win total by ~ 1 win by getting Santana.
Looking at it that way, in a vacuum, it would be a wash. But obviously you can't look at it that way. You have to question which way provides the most risk and reward. Lackey, IMO, is a bit of a regression candidate (FIP a tick higher than ERA). Hanigan coming off an injury also provides a great deal of risk. On the other side, Santana catching 100 games isn't ideal behind the plate, and trusting Brandon Workman to give you 30 starts is risky as well (though you also have Barnes right behind him ready to step in if needed).
Personally, I would rather have Santana and Workman than Lackey and Hanigan, not just for this year, but for the years going forward. I don't think it's a downgrade in the short term, and I certainly think long-term it benefits the team.