Presumably if you prefer to play "tall" you build defense stations to protect the entrances to your territory.
You should probably be doing this playing "wide", too, to be fair. Defensive works make for some serious force-multipliers, and until jump drives arrive into the fray, being able to lock down choke points with static forces lets you free your mobile forces to actually do some damage. Enemy raiders can be rather irritating, otherwise, so stopping them from moving into your space with either planetary FTL inhibitors or orbital FTL inhibitors is a strong plus. A good fortress or citadel in the mid-game can easily equal a proper fleet, even if it can't move, and it runs off the starbase caps instead of your fleet caps.
Also, I feel like jump drives are an even bigger game changer now than they were in older hyper-only games, even with the cooldown times. I'm running hyper lanes a bit sparse (experimenting with 0.5-0.75) and they tend to be a bit snaky compared to previous patches. When I have two stars spatially adjacent that have easily a dozen jumps between them, jump drives have cut transit times across my empire in half. They're probably not as critical if you set the game options to denser arrangements, but they're even more valuable than I thought, and I already expected them to be pretty darn valuable.