Extra virgin olive oil is slightly bitter, so it might create a bitter taste aftertaste. Offsetting with a neutral oil like avocado or grapeseed will create a more balanced flavor profile. However, you can use all olive oil and omit the avocado oil.
If you’re concerned with that fat/calorie content, you can increase the amount of water and equally decrease the amount of oil. I recommend using at least half of the oil for texture purposes.
Taste the avocado before adding it to the blender. Older avocados can develop an unpleasant flavor. Ideally, you want to use a fresh tasting avocado!
Some recipes use plain yogurt in place of avocado for creaminess. You can do this, but keep in mind that yogurt has a tangy flavor, so that combined with limes will create more acidic results.
If you want less sweetness, try decreasing the honey to 1 or 1 1/2 tablespoons. Taste; add more if you think the dressing needs it.