Hmm... I actually wouldn't feel bad about taking a tarp (rather a poncho as far as personal preference) over a tent. Unless the weather is very cold or rainy and the environment totally barren I wouldn't bother with a tent any longer. It's a lot of extra bulk and weight that most of the time simply isn't necessary. I've slept under a poncho lean-to in many kinds of terrain and weather, including heavy rain, and it always did a good job.

But I agree it's not for the inexperienced or faint of heart. If you're not used to the outdoors and if the thought of bugs and snakes scares you to death you will be more comfortable in a tent. Though you will be less comfortable lugging around that tent on longer hikes and you'd better practice setting it up at home so that you can do it quickly outdoors even in poor weather.