If you only play hands you can raise with then it would be a lot easier to read you and know you're playing a range of strong hands. Someone who constantly limps could be playing anything. I think in the long run though raising and playing good cards will be more profitable. People who play bad cards and suck out will be less profitable. I'd say take your bumps here and there but keep playing your game.
You do realize that poker is a game that strongly punishes second best hands, right? And, in logical response to that fact, you should only be playing a strong range of hands! So, in the last logical step, if you are the first person in the pot, the only playable hands should be ones strong enough for a raise. If your hand is not strong enough for a raise, it isn't strong enough to play. Actually, you would need a stronger range for open-limps than for open-raises, because you are giving up a significant part of any hand's equity (fold equity) pre-flop.
What defines a strong range depends on your position, number of opponents, their ranges and your expected position after the flop and the expected number of opponents after the flop. So, A9o might be a fold UTG because it is likely too weak for those conditions, but it would be a raise on the button, because it is part of a strong range there.
Open limping is a losing play. It is nearly impossible for it to be part of a well structured winning no-limit hold'em strategy.
Edit: This does make it easier to read you than someone playing a 100% range, but it doesn't make your hand obvious. An 18% range is still a very large number of combinations and will hit a large number of flops. And, often, even knowing that someone is playing a strong range doesn't provide you any advantage because their range is too strong for you profitably exploit that knowledge.