Not by default — a subdirectory of the corporate domain usually inherits more search authority and is easier to govern, and a fully separate domain is typically justified only by a distinct brand identity, unbranded content requirements, or a genuinely separate audience and market scope.
A subdirectory structure benefits from the corporate domain’s existing search authority and is simpler to govern under one technical and compliance framework. Splitting to a new domain starts that product’s search presence closer to zero.
A genuinely distinct brand identity the corporate domain would dilute, unbranded disease-awareness content that specifically needs separation from anything branded — see disease awareness website — or a product with materially different market or regulatory scope.
Whichever structure is chosen, the content architecture and, if separate, the technical relationship between domains needs to be deliberate — see product website for how that gets built either way.
Not necessarily; visual identity can be fully distinct within a subdirectory structure, since the URL choice and the brand presentation are separate decisions. A product can look and feel entirely its own, with its own design language, while still sitting under the corporate domain from a technical standpoint.
That is one of the clearest cases for a separate domain, since unbranded disease-awareness content specifically needs separation from anything carrying a product name or branded claims, for regulatory as well as editorial reasons. See disease awareness website for how that separation is typically structured and maintained.
Yes, though it requires the same careful redirect mapping and search visibility preservation as any other migration, not a simplified version of it because the sites were related beforehand. See SEO migration for how that consolidation is planned so the existing domains’ search authority is not lost in the move.
Largely yes, provided the redirect mapping is built individually rather than as a blanket rule, and external links are given time to be recognised at the new location. Some loss during the transition is normal, but a carefully planned consolidation preserves most of the accumulated authority rather than starting over from zero.
Tell us your product and brand situation and we will tell you what actually fits.