50%+ stake in a JV is OK. Why there is a need to question it.
LCA itself will not be produced by this JV, only some components.
It is better that components be made in India, rather than being imported. We shall lose control in case of imports. We need to substitute imported components, as well as redesign some to save space. I think the main requirement is internal EW systems, where HAL needs help. SAAB is the logical partner, as Gripen is almost same size as LCA, and IAF's wishlist more or less mirrors Gripen's capabilities.