Not exactly. I am a huge fan of code modularization, but what modularization offers you is the ability to decrease the exponent (i.e. to be devTime^1.01 instead of devTime^2). Some features though (including segment tuning, from the sound of it), will touch a ton of other features regardless of how well you modularize your code.

I work at a networking company (Arista), and a lot of the interesting problems come from this sort of interaction. Our entire OS was built so an agent would be resilient to changes in another agent, and this modularization means there is very little "spaghetti code". However, when you are building a feature (say, a new routing protocol), you have to be extremely conscious of how it interacts with everything else: various reliability features (i.e. Stateful switchovers), configuration features (saved configs, public APIs), resource contention (TCAM utilization), etc. etc. If that new routing protocol was the first thing we implemented on our switch, it would be a complete breeze. In the context of other features though, this becomes a more intensive project (though in codebases without proper modularization you'd find this task "herculean" as opposed to "intensive").