You will need venting capability wherever you have a cooktop module. Multiple locations require multiple venting.

You are committed to the module cutout(s), just as you would be with any cooktop. However, any unit should be fairly easy to swap out, as long as it is still being manufactured. You could pick a different module later assuming you have the proper power source for it. Gaggenau & Miele also offer module cooktops besides Wolf.

We initially planned to do what you are considering. Modules should let you pick & choose exactly what you want where.

The look of modular cooktops means they all have to be from the same manufacturer, but I discovered that the function provided by each module wasn't always the most powerful or versatile. There wasn't one manufacturer's line that offered everything I wanted.

Another disadvantage is cost--the modules are more expensive than conventional ways to provide the same functions.

We ultimately decided to provide multi-cook functions with appliances in addition to cooktops:

Gaggenau combi-steam oven instead of countertop steamer, for more capacity & small convection or reheating oven.

DCS 36" all gas range with 6 burners, all continuous grate. 17,000 BTU on 4 burners, low simmer power on the other 2 burners, & we can span burners for big pans. Infrared broiler & monster oven for entertaining.

However, we still included two modular 15" cooktops, flanking each side of the range:

Gaggenau single hob induction burner, 3500W or about 32,000 BTU, for stirfry, boiling water for pasta in 6 minutes, or anytime DS wants flame free cooking.

Gaggenau teppanyaki griddle-style grill. Still learning this one.

Bottom line: we spent as much as the original 4 modules we planned, but I think we have a lot more capacity & versatility. We needed the same hood for either option.

We also have a wall Advantium (speed cooker & microwave) & a 27" convection oven (Gaggenau) but we planned to include those regardless of the cooktop decision.