Philosophically, I'd acknowledge that Sega is one international company, and that there is a niche/core of fans that are aware of what is going on in each territory. With the advent of the web, anything that SOJ does is known to fans in the West within a day whether or not Sega announces it. So, I'd embrace that. I'd establish a text-only localization facility that works to bring over titles that have a small but reliable fanbase in the West. And I'd do it in a way that makes fans feel involved. Let's say we budget a localization effort that brings over four titles per year. Three of them could be selected in-house, and the fourth could be selected via a series of polling events. Big titles like Yakuza and PSO2 should not only be localized, but released in sync in the West.
I'd have the website redesigned to be more similar content-wise to the Japanese site as well, with information about Sega's long history, and featured interviews with developers from all eras.
I'd establish a service model for ongoing access to the Sega back catalog, similar to EA's recently announced Netflix-style subscription but with more content spanning the entire console and arcade history, as well as selected recent titles. Charge a reasonable monthly or annual fee and let gamers have access to hundreds of games in a curated collection. Feature special events like weekly high score competitions to shine a spotlight on various older titles. Use some of the income from this subscription service model to fund the ongoing Sega Heritage HD update series.
There's still a market for consumers who would find Sega-branded hardware appealing, so I'd establish a hardware division that manufactures Steam Machines and configurable gaming PCs that have a high margin, perhaps in partnership with an established manufacturer like Dell/Alienware.
Part of the unifying of the company to operate as a whole would include establishing a pipeline to release home versions of arcade titles within a year of their arcade debut. Games like Border Break would be brought home with functionality and player character persistence that can transfer back and forth to the arcade, enhancing arcade revenues rather than undermining them.
I'd shut down all in-house marketing and hire established high-end marketing firms in each region to handle all PR campaigns.
I'd re-establish the uniquely branded internal development team model and place an emphasis on attracting new talent with smaller, more agile teams. New hires who are exceptional should be able to progress to leadership positions on development teams within 8 years.
Lastly, I'd personally take on consulting duties for the continuing series Outrun, Shenmue, and Jet Set Radio. :D