As offshore wind power migrates into deep, remote waters, the traditional single-source electricity-export model faces severe techno-economic fragility, primarily driven by prohibitive offshore transmission costs and finite onshore grid absorption capacity. To overcome these barriers, this structured review examines the transition from standalone wind farms to multifunctional integrated energy systems through a holistic resource-grid-load integration framework, within which generic objectives, balance relationships, operational constraints, and validation approaches are summarized as a standardized modeling reference. On the supply side, the analysis evaluates the spatiotemporal synergy of coupling wind with floating photovoltaics, wave energy converters, marine biomass, and ocean thermal energy, demonstrating how multi-energy complementarity dampens output fluctuations and enhances structural stability. On the demand side, the study critically explores diversified in situ utilization pathways, specifically low-trophic marine ranching, seawater electrolysis for green hydrogen and ammonia (Power-to-X), and the electrification of legacy oil and gas platforms. These demand-side load reconfigurations transform surplus electricity into storable chemical carriers, effectively relieving pressure on long-distance transmission corridors. Furthermore, this review addresses the strict geographic and economic boundary conditions of these pathways, indicating that preferred export and utilization pathways depend on distance, water depth, project scale, metocean conditions, market readiness, and cost assumptions. Finally, by assessing the technology readiness levels and intrinsic limitations of current configurations, this study proposes a three-stage research roadmap, providing the theoretical and methodological grounding necessary for future autonomous deep-sea multi-carrier energy hubs.